Residential Burglary: Main Results of a Study in Germany

Unlike most criminal offenses in Germany, the rate of residential burglary has significantly increased since 2006. This high number of burglary cases is contrary to a very low rate of suspects actually identified by the police. However, official statistics indicate that individual districts in Germany strongly differ regarding the frequency rate as well as the number of suspects. Hereby, the Criminology Research Institute of Lower Saxony conducted a comprehensive study on residential burglary regarding the characteristics of burglary offenses, the situation of victims, criminal investigations and legal proceedings, as well as the characteristics of offenders. Written surveys were completed with victims of burglary (N=1,329) and criminal files were analyzed (N=3,668). The present paper represents the main results of this research project.


Introduction
In the past two decades, the official crime statistics collected by the police indicate that Germany is becoming an increasingly peaceful country: from 2000 to 2015, completed murder and homicide offenses declined by 40.45%, bodily injuries with death by 72.49%, robbery by 23.93% and sexual assault by 10.30%. In contrast to this general crime trend, residential burglary 1 has increased since 2006 from 106,107 cases to 167,136 offenses in 2015, which is an increase of 57.52%. Even between 2014 and 2015 burglary offenses have had a growth rate of 9.87%.
The high number of burglary cases is contrary to the very low rate of suspects actually identified by the police (15.2% in 2015). However, individual districts in Germany strongly differ regarding the frequency rate as well as the number of suspects, as will be illustrated by the example of five cities mentioned below.
Previous research on burglary has mainly focused on the psychological strain of victims [1][2][3][4][5]. Hereby, the main results show that burglary victims often suffer from several anxieties after the offense. Given that most studies were conducted a short time after the burglary, fewer studies have emphasized long-term strain and change in behavior. Furthermore, little is known about the perception and role of the police regarding the interaction with victims.
Research on the criminal investigation process in Germany is mostly restricted to a specific regions [6,7]. Among others, the study showed that over half of the criminal proceedings against a suspect were stopped by the prosecutor, whereby the clearance rate is very low. Given that previous research has focused on a specific region, there is a gap of research concerning an explanation of the differences between the regions.
Research on offenders deals with the problem that the police only caught a small proportion of burglars. Due to the low number of sentenced offenders, studies often analyze information of suspects of criminal files [7,8]. The findings indicate that most of the offenders -respectively suspects -were male, whereby other personal 1 According to the German criminal code in § 244 Abs.3 Nr. 1 StGB, residential burglary is defined as the unlawful entry into a building, e.g. a house or apartment, with the intention of stealing. This definition does not include other structures such as basements, gazebos and tents. If a person fails to enter the building or no theft is committed, it is only classed as an attempted burglary. The burglary rate of the police crime statistics involves completed as well as attempted burglaries. characteristics were not clearly distributed. For instance, 26% of the suspects committed the crime with at least one other person and in 39% of cases the offender and victim knew each other [7]. Other surveys have interviewed (arrested) burglars [9][10][11][12]. Among others, the findings of these interviews indicate that offenders commit burglaries to satisfy different needs that evolve from financial problems as well as the demand for a specific material status. Concerning the criminal action, burglars mostly try to break in quickly and avoid attracting attention.
The findings of the police crime statistics and the gaps of research formed a starting point for the Criminological Research Institute of Lower Saxony to initiate a study on residential burglary 2 . This study looks into the following research questions: • What are the characteristics of residential burglary?
• What is the situation of the victims, especially regarding psychological strain and behavioral changes?
• How do the criminal investigation and the legal proceedings proceed?
• Who are the offenders?
The present article outlines the main results regarding the research questions mentioned above 3 .

Methods and Samples
The survey was conducted over a period of three years between 2013 and 2016 in Berlin, Bremerhaven, Hannover, Munich and Stuttgart 4 . The chosen cities were selected due to their differences in frequency rates 5 , the number of suspects and investigative procedures ( Table 1). The contrasts of the cities ensure an opportunity to analyze several research questions. For instance, having cities with high rates of suspects allows analyzing which factors influence suspect rates and if they are relevant regarding the clearance and conviction rates. Furthermore, the approach of comparing five large cities enables examining regional differences; for example, with respect to different types of offenders.
Two different research methods were used to underpin the broad research focus, namely a quantitative analysis of 3,668 criminal files and a quantitative written survey of 1,329 victims.
First, 2,500 cases were randomly selected from offenses defined as burglaries by the police crime statistics in 2010 6 . Of the 2,423 files that could be obtained, only 2,403 were analyzable. Due to the low rate of suspects, it was expected that a random sample would contain only a few cases involving suspects and sentenced offenders. As a result, a second sample was generated from crimes that were registered by the police as having at least one suspect; thus, an extra 1,265 criminal files could be added. Overall, 3,668 analyzable criminal files were taken for file analysis, whereby 1,606 files involved at least one suspect.
The file analysis yielded 2,299 households that could be contacted for the victim survey. The (adult) household member whose birthday was most recent was requested to participate in the survey. Three forms of contact were used (announcement letter, questionnaire, and reminder), of which the questionnaire letter contained 5 Euros as a monetary incentive. A special procedure was undertaken if the first letter was returned as undeliverable; for example, if the owners had moved household. In such instances, the owners were contacted through information provided by registration offices.
A total of 2,024 questionnaires were sent to households, of which 1,391 were completed and returned to the research institute, reflecting a response rate of 68.7%. In some cases, questionnaires were only partially completed or persons other than the victims had completed the questionnaire, such as family members. This reduced the number of included questionnaires to 1,329.
Of the individuals who participated, 53.2% were women. The mean age was 52.9%, with participants ranging from 18 to 97 years. More than half of the victims (54.9%) had a high education level, as measured by the participants' highest level of educational attainment. This result may stem from the fact that the survey was only conducted in large cities. The majority of participants lived in a family environment with children or a partner (60.9%), 36.1% lived alone and 3.1% lived in other household situations.

Characteristics of burglary offenses
Almost two-thirds of the victims had experienced a completed burglary (64.9%) 7 and a further 35.1% of the victims had experienced an attempted burglary, whereby in 30.0% of the attempts the offender 4 In the following, findings were presented for all cities in total. Differentiated analyses per each city were only made if there are relevant differences in the data. 5 The frequency rate indicates the number of offenses per 100,000 inhabitants. 6 The sample was based on cases from 2010 to ensure that any files used were no longer needed for criminal proceedings and thus were usable for the research. 7 The results regarding the characteristics of residential burglary are based on the victim survey. entered the house 8 but did not commit a theft. The results indicted no significant difference between the five cities.
Most burglaries occurred at the end of the year, during the socalled "dark months". Here, the rate steadily increases from September onwards and peaks in December. The summer months -and thus the vacation time -are very low affected. A possible reason for this may be that burglars take care in avoiding break-ins when someone is at home. During the dark months, it becomes easier to recognize from the streets whether someone is at home because the lights are turned on. This explanation fits with a second finding concerning the time of crime: 81.0% of the burglaries happened during the daytime -e.g., between 6 am and 9 pm -which is the time when most people are working 9 .
Supporting the idea that burglars avoid contact to the victims, only 20.1% of the burglaries occurred while someone was at home. The number of victims who noticed the offender (8.4%) is much smaller and only 4.2% of all victims had direct contact with the burglar. Burglaries involving physical violence against the victim only occurred in individual cases (0.7%).
Concerning the proceeding of the offender, in 77.2% of the cases the burglar broke or pried a door or window. In a further 11.3%, glass was broken to enter the house. Damaging or manipulating the lock with a tool or false key only happened in 8.5% of the burglaries. Using an open or tilted window only occurred in 7.1%. However, the burglary attempt was not successful in all cases. Asked for the reasons why the offender failed to enter the house, 41.1% of the victims cited the security of the door and a further 24.6% mentioned the security of the window or a French window. Besides these techniques, other people were also relevant, given that in 15.2% of the attempts when the offender failed to enter a person outside the house -e.g., a neighborprevented the offense and in 14.5% it was a person inside the attempt. 2.0% mentioned other reasons and 14.1% did not know why the burglar did not finish his attempt. To summarize, technical safety precautions had the highest relevance.
Furthermore, the victims of completed burglaries were asked for the amount of damage suffered. The average monetary loss of the stolen items was 9,032.59 Euros, whereby the median is about 2,500 Euros. Almost one-third suffered damage over 5,000 Euros. There is no significant difference between the cities. However, victims differ regarding their age, with older victims encountering higher monetary losses.
Damages aroused not only due to stolen things but also through further damages in the house due to the breaking in or vandalism behavior. The average monetary costs of the further damage of victims of attempted or completed burglaries were about 1,372.80 Euros, while 8 Residential burglary refers to houses as well apartments. However, for simplification, the present paper uses the term "house" to also mean apartments. 9 It must be noted that most victims could only indicate their period of absence when the burglary took place. In the analysis, we took the mean of the time period.

2012
Berlin Bremerhaven Hanover Munich Stuttgart Germany the median is about 500 Euros. Only a few people noticed a further damage below 50 Euros. Despite no significant difference between the cities and regarding age, there is a notable difference related to the state of the offense: in comparison to attempted burglaries, completed crimes are associated with higher further damage.

Number of cases
82.4% of the victims mentioned damages at the place when the burglar broke in. 42.2% of the victims who experienced a burglary where the offender entered the house agreed with the statement that there were devastations due to the offense. 37.8% mentioned dirt and in 31.0% of cases things were destroyed. In most cases (68.1%), the offender rummaged among personal belongings. The condition of the house after the burglary differs between the cities; for instance, the strength of agreement with the item "The house was devastated because of the burglary" ranged from 29.2% to 62.0%. Indeed, this might be an indication for different types of offenders.

Situation of the victims
To measure the situation of the victims, they were asked for psychological strain, changes in behavior and their experience with the police 10 .
Psychological strain: First, the victims were asked how strongly they agree with several items concerning psychological strain after the burglary (Figure 1). Hereby, they could specify how long they felt strained. For the findings presented below, the time periods were summarized as either within the first eight weeks after the offense or longer than eight weeks. The results indicate that a feeling of insecurity in familiar surroundings reflects the strongest longer-term effect with 46.5%, followed by feelings of being powerless or helpless (39.9%). Stress and tension is distributed especially within the first eight weeks after the burglary (38.1%). 20.2% of the victims had severe anxiety for longer time and almost the same amount suffered sleeping disturbance (18.5%). To a lesser degree, people felt disgusted for longer periods (13.9%) and humiliated (15.9%). However, some victims wanted to think about what happened (13.3%). Besides the sleeping disturbances 10 The following results regarding the situation of the victims are based on the victim survey. mentioned above, 12.5% of the interviewees had nightmares for a longer time. 10.1% agreed with the statement that they felt insecure dealing with other people longer than eight weeks after.
In the longer term, women are more affected by feelings of anxiety and insecurity as well as being humiliated and powerless compared with men. Older victims as well as younger ones had feelings of anxiety and insecurity for a longer time. Regarding the influence of characteristics of the burglary, the effects appear as excepted: completed burglaries influence psychological strain as well as devastation and destruction to a greater degree than attempts due to the offense.

Moving behavior:
The findings suggest that a burglary affects the well-being in one's own home. To measure this aspect in further depth, the victims were asked whether they had changed their residence since the burglary happened. Interviewees who affirmed the question were asked why they moved based on several items, six of which were related to the burglary: • The house/apartment reminded me of the criminal offense.
• I had the feeling of the offender still being there.
• I did not feel safe in the house/apartment any longer.
• I was disgusted by the house/apartment due to the burglary.
• My partner wanted to move due to the offense.
• Another person than my partner wanted to move due to the offense. 9.7% of all victims mentioned at least one of these reasons to move. Moreover, a further 14.8% had the desire to move owing to the reasons mentioned above. To summarize, almost one-quarter of the burglary victims had the desire to move or even did so owing to the experience offense. That is an indication for the dimension of the impact of a burglary on the life of the victims. experience with the police. Most victims (74.1%) indicated that they waited for the police for less than one hour. In over half of the cases (55.3%), the police only came once to the affected house. In 9.5%, the police sought out the victim more than twice. There are significant differences between the cities, with a range of 3.8% to 15.2% in terms of the cases in which the police came more than twice. The survey also shows differences between the cities concerning the length of the first visit of the police, whereby the average time ranges from 40.6 to 84.9 minutes.
Furthermore, the victims were asked for their perception of the police by several items (Figure 2). Hereby, they were asked how strongly they agree with the items. Victims could also answer with "cannot judge" if they did not know about the activities of the police. For instance, this might be the case if other household members than the interviewees were involved in the contact with the police. Only 5.6% mentioned that they were strained by the criminal investigation. Moreover, a small amount of 13.7% had the perception that the police were under time pressure. 28.3% agreed that the police consulted all possible witnesses, whereas 43.8% could not give an estimation for this. Almost half (49.5%) denied the statement that the police kept them updated. Nevertheless, 58.8% of the victims felt better following the talk with the police. Almost 80% agreed that the police did their best to find marks, they were satisfied with the police work and perceived the police as competent and professional. More than 80% agreed with the item that the police took sufficient time for talks, felt that they had been taken seriously and described the police as friendly and helpful.
To conduct differentiated analysis regarding the perception of the police, the eleven items were reduced to three dimensions: social interaction 11 , investigation 12 and general satisfaction 13 . Separated 11 Hereby, scales of the mean value of following items were built: "I experienced the police as friendly and helpful", "I felt taken serious by the police", and "The police took enough time for talks with me". Cronbach's alpha for this scale is .84. 12 The items "The police did their best to find marks", "The police asked all possible witnesses", and "The police kept me current about the investigation" were reduced to a mean scale. Cronbach's alpha is .61. 13 General satisfaction is operated with the single item "All in all I am satisfied with the work of the police". according to city, there are no significant differences: social interaction is highly rated in all cities, with over 90.0%. Furthermore, the general satisfaction is high (over 80.0%). The valuation of the investigation is not as good as the social interaction, although over the half of the victims are satisfied with this in each city.

Criminal investigation
Regarding the criminal investigation, the research interest was to explain the major differences in the rates of suspects between the cities and which factors influence the rate of sentence. Furthermore, a relevant research question was why there are so many cases in which the police has found suspects and the prosecutor still stops the proceedings 14 .

Differences in criminal investigation:
In a first step, differences in criminal investigation between the cities were analyzed. Hereby, it was tested what impact these differences have the regarding the rate of suspects and sentences, respectively.
There are major differences between the cities regarding the organization of the police as well as the criminal investigation. One possible reason for this might be due to differences in the size of the city. For instance, there is one city in which the first contact of the police is almost always undertaken by a lower-ranked police unit, whereas there is another city in which the first contact is engaged by the criminal police. The number of cases that were exclusively handled by the criminal police varied between 15.0% and 41.3%. However, there are no relations between the ranking of the police officer and the rate of suspects or sentences.
Furthermore, there is a major difference between the cities according to the number of cases in which the police searched for marks, ranging from 76.1% to 97.6%. The number of cases in which the police found marks ranges from 26.4% to 78.0%. Nevertheless, marks only led to an investigation of a suspect or the confirmation of a suspicion in three out of 100 cases. Marks that were most relevant were fingerprints and DNA traces. The number of cases in which the police 14 The following results stem from the criminal file analysis. I felt the invetsigations to be a strain.
(rather) no (rather) yes cannot judge asked witnesses ranges from 61.2% to 99.0%. Even though around twofifths of the witnesses could provide information regarding the offense, this only led to the investigation of a suspect in eight out of 100 cases. Traces and witnesses might be relevant for the investigation. However, the police have no influence on the evidence on the crime scene, nor the number of relevant witnesses.
Further differences between the cities evolved according to the number of cases in which relations were established with other burglary cases, ranging between 11.0% and 27.1%. The reasons for the relation are mostly due to similarities in time and space, as well as the same modus operandi. The aspect whereby cases were seen in relation to each other by the police is relevant regarding the official crime statistics of the police. If there is a suspect for one case and this case is seen in relation to other cases, all of these cases were counted as cases with a suspect in the statistics. Accordingly, bringing cases in relation to each other might increase the rate of cases with suspects.
The differences between the cities in terms of the number of suspects ranged from 9.9% to 24.8%. However, there are no statistically significant differences in the number of cases with at least one sentenced offender (1.5% to 3.6%). Cities with a higher number of suspects are those in which more cases with suspects were dismissed by the prosecutor. Moreover, cities with higher numbers of suspects have more cases in which the suspect is reasoned due to making a relation to another burglary offense.
To analyze influence factors on the rate of cases that ended up with at least one sentenced offender, a regression model was calculated ( Table 2). The chance that a case with a suspect ends up with a sentence is reduced in city 2 and 3 in relation to city 1 when it is a completed offense, when there are indications of drug addiction, a police interrogation with a confession or indications that several offenders conducted the burglary together. In addition, the chance is higher if the suspect is investigated due to the testimony of an accomplice, fingerprints or DNA traces, captured near the crime scene, as well as due to stolen goods. On the other hand, the chance is reduced that a case ends up with at least one sentenced offender when the offender and the victim know each other or if the investigation of the suspect involved making a relation to another burglary due to the manner of proceeding the offense.
Dismissal proceedings: A further question of research was what happens to the cases in which the police investigated at least one suspect. In the data of the file analysis, 1,606 cases involved at least one suspect. Overall, there were 2,471 suspects involved in these cases. However, only 598 of these were charged by the prosecutor, whereby 506 persons were sentenced. In other words, only 30.0% of the proceedings were continued by the prosecutor, whereas 69.0% were dismissed. This means that only 2.6% of the cases ended up with at least one sentenced offender.
The most common reason for the prosecutor to dismiss the proceedings even if a suspect is investigated by the police is due to insufficient grounds for suspicion, whereby 52.0% of the proceedings of suspects were dismissed due to this reason.

Characteristics of offender
Based on the offender characteristics, there are two main results 15 . First of all, there is not one homogenous type of burglar, aside from 15 The findings of the characteristics of the offenders (N=506) derived from the case analysis. Hereby, an offender means a sentenced person by the court in contrast to a suspect.
in terms of gender, whereby 90.1% were male (Table 3). 66.0% of the offenders lived in the city in which they committed the burglary, whereas 11.0% came from another city or country and 23.0% did not have a permanent residence. 56.7% were born in Germany and slightly fewer (49.6%) had German citizenship. There is also no consistent finding regarding the question of whether burglars prefer to act in groups: 45.0% conducted the burglary together with at least one other person, whereas 55.0% handled alone. A little more than one-third (38.5%) had a kind of addiction, referring to drug as well as gambling addictions. Surprisingly, 32.4% of the offender had a kind of relation to the victim. For instance, these were former love relationships or problematic acquaintances.
Even the characteristics are not spread uniformly; rather, there are different types of offender regarding the city level (Table 2). In  particular, city 2 and city 5 strongly differ. Whereas in city 2 most of the offenders (86.7%) live in the same city in which they committed the burglary, this is only the case for 44.2% in city 5. Furthermore, in city 5 more offenders (70.3%) have another citizenship compared with city 2 (30.2%). Moreover, the range of addiction from 18.6% in city 5 to 52.3% in city 2 is remarkable. To summarize, the results indicate that city 5 has many offenders from abroad who simply go to the city to commit residential burglaries before moving on. By contrast, city 2 has many offenders in town who have social problems in the form of addictions. Other cities such as city 1 have several different types of offender (Table 3).

Conclusion
Unlike many other crimes, since 2006 burglaries have been on the rise in Germany. Hereby, the police crime statistics indicate huge regional differences regarding the frequency rate as well as the number of suspects. The aim of the presented survey was to conduct a multiperspective study of the phenomenon of burglary crime in five large cities in Germany. Accordingly, the focus of the research was placed upon the characteristics of the offenses, the situation of the victims, the criminal investigation and legal proceedings, as well as the offenders. For this purpose, 1,329 victims were interviewed by a written survey and 3,668 criminal files were analyzed.
In conclusion, the results indicate that most victims suffer from psychological strain and change their behavior due to the burglary experience. Knowing that victimization without contact between the victim and the offender can be harmful is important for victim support organization as well as for the police, who are often the first person who victims call after noticing the burglary. Therefore, police officers should take the situation of the victim seriously and take time for the victims, as well as providing them further information on contact persons who might help them.
Regarding the offenders, the results show that there is not one particular type of offender. Nevertheless, there are specific types in some cities, whereby some cities have more offenders from abroad and fewer burglars with addictions compared with other cities. This finding can be interpreted as an indication of different regional causes for burglary crimes. From a broader view, this emphasizes that causes of delinquency are not solely given in other countries where people are poor. Moreover, delinquency structures are also given in German cities themselves. Police investigation and local prevention programs should acknowledge this by considering the specific situation on-site, given that procedures that work in one city might not be the best approach in another.
Concerning the police investigation, the results regarding the rate of cases with a sentenced offender indicate that there is no huge difference in the quality of the police work. Moreover, burglary seems to be an offence with a low investigative approach. The reasons for this might be the fact that most victims do not see or know the offender, whereby the cases seldom have traces or witnesses. Nevertheless, if the police find fingerprints or DNA traces, the chance that the burglar can be found increases. Accordingly, the results stress the importance of the quick analysis of the traces.
Given that most burglaries happened during the day, especially in the dark months at the end of the year, effective preventive measures can be derived. Given that burglars are focusing on apartments and houses were the dwellers are absent, it might be a possibility to turn lights on even if someone is not at home and avoid signs of absence such a full mailbox. However, more profound studies are necessary to learn more about effective preventive measures.
Due to the methodological approach, the study entails a few limitations concerning the specific explanations and generalizability. For instance, the victim survey only involves victims who reported the burglary to the police. Furthermore, the interviews were conducted approximately three years after the criminal offense, which is a benefit regarding long-term consequences yet reflects a disadvantage in terms of remembering the situation right after the burglary. In addition, the individual statements of the victims about the police work might be biased through mentally strain like a shock. Likewise, the victim survey and the case file analysis only deals with information known by the police. Due to the small number of sentenced offenders, deeper differentiations between different types and groups of offenders and between the regions cannot be made.
The limitations mentioned above offer starting points for further research. Despite the fact that there is a lot of research concerning the situation of victims, little is known regarding influence factors of coping and resilience. Furthermore, there is a gap of evaluations regarding the different strategically and tactical focus of police work, particularly concerning the investigation and prevention work. Moreover, there are still many questions about the offenders: Who are the offenders in the 75% of cases in which the police have no suspects? Are there specific types of offenders who differ in their manner of crime action? Are there any relations to other crimes such as vehicle theft or burglary in businesses? With the method used to analyze the offenders, it is assumed that only a very selective group of offenders is reached. Therefore, further research projects should consider new approaches to obtain information on burglars.

Funding
The study is funded by the cities of Berlin and Bremerhaven as well as the German Insurance Association.  Table 3: Characteristics of offender in comparison with the cities (in % aside from age; bold: differences are statistically significant).