Social networks have always an important place in criminological theories. Despite their clear theoretical importance in explanations of crime and criminal behavior, social networks are all too often measured indirectly or not at all. Social network analysis (SNA) provides scholars with a set of measures, techniques, and models to directly investigate the impact of networks on behaviors but criminologists have taken longer than scholars in other fields to adopt SNA. Recently, scholars have begun using arrest and Field interview (FI) records to extract relationships between individuals encountered by the police. This dissertation provides a first critical analysis of the implications of using police records to study criminal social networks. I examine to what extent these networks reflect the behaviors of actors involved in them or the behaviors of organizations that observe them. I provide an in-depth description of the nature and content of arrest and FI records that are critical to the construction of social networks. I explore sources of variations in police records based on police organizational changes such as changes in leadership, and reduction in the size of the police force, and police adaptations to important legal changes that occurred in recent years in California. I also test the influence of civil gang injunctions on both the patterns of associations of gang members targeted by them and the behavior of officers enforcing the injunctions. I discuss the implications of using these records to measure criminal social networks.

While violence across the United States has declined dramatically over the past two decades, gang-related crimes remain at unacceptably high rates, especially within the city of Los Angeles, America's gang capital. Gang-related crimes generally involve groups of individuals and have a strong territorial component, lending themselves to geographically targeted interventions. A strategy that has charmed law enforcement agencies with its ability to take advantage of both the social and spatial features of a gang is the civil gang injunction (CGI). Essentially, a CGI is a tailored restraining order against a gang, prohibiting its members from engaging in specific nuisance behaviors within a demarcated geographical region, termed a "safety-zone." Evaluations suggest that CGIs are effective at reducing serious crime and residents' fears; yet, CGIs remain a time-consuming and costly strategy with an unstudied mechanism for why they work. Do CGIs influence how gang members associate and where they hangout? And, more importantly, how do CGIs contribute to changes in gang violence?

Using the framework of routine activities theory, this dissertation focuses on the relationship between CGIs, gang members' patterns of association and lethal violence. To address these questions I utilize two unique datasets: homicide case files and field identification (FI) cards gathered from the Hollenbeck Community Policing Area of the Los Angeles Police Department. My first chapter utilizes social network and spatial analyses to investigate the patterns of association among enjoined gang members at the individual- and group-level. I examine both the characteristics of enjoined gangs' social networks, ascertaining their influence in disrupting social ties, as well as examining the geographic characteristics of FIs to discern if enjoined gangs have changed the spatial patterns of their associations. My second chapter looks at both the homicide trends over the last decade and the disparities between non-gang and gang homicides, both enjoined and non-enjoined, to consider how CGIs influence the characteristics of violence. Lastly, in my third chapter I construct a turf-based spatial typology of gang homicide to investigate the impact that CGIs have on the mobility patterns of participants involved in gang-related homicides. If CGIs influence gangs' spatial patterns of association by discouraging members from congregating in public, then a CGI in theory shifts members' activity and travel patterns, suggesting that gang homicides involving enjoined gang members would experience a different mobility pattern than gang homicides involving only non-enjoined gang members.

Results from this dissertation indicate that CGIs are able to influence the patterns of association of individual gang members, particularly in the short-run. Conversely, at the group-level, enjoined gangs do not always respond as predicted by the rational of a CGI, with a gang's social network either being disrupted, with members' social ties losing connectedness, or a gang's social network converges, with members' social ties increasing in connectedness. It also appears that while CGIs are able to dislodge enjoined members from their gang's hangouts, a CGI actually constrains the overall mobility of enjoined gang members, reducing the likelihood that enjoined gang members are venturing outside of their gang's claimed turf. In relation to influencing the overall patterns of gang violence, the findings suggest that CGIs could be shifting enjoined gang homicides away from the street and into less public spaces, along with involving fewer suspects and victims. Results also indicate that the presence of CGIs in Hollenbeck has impacted the mobility patterns of participants who are involved in a gang homicide. Specifically, an increase in internal gang homicides and a reduction in predatory gang homicides were observed in the data. These findings are consistent with earlier results indicating that the mobility of an enjoined gang member is restricted by the presence of a CGI. Overall, the goal of this dissertation is to provide both scholars and criminal justice professionals with a better understanding of CGIs, and ascertain if they are an appropriate strategy to disrupt a gang's patterns of association and diminish their opportunities to participate in violent acts.

Scholarship on hate crime in U.S. neighborhoods has yet to learn from Los Angeles; this dissertation addresses that empirical gap and provides theoretical assessment of what hate crime law has wrought over the last three decades in California and the United States. The picture is generally of expansion and then decline in use, while the best evidence shows that rates of hate crime victimization remain unchanged. Originally conceived as a statistical monitoring system, hate crime law currently monitors its own infrequent use by police across the United States. The system appears broken; public interest in and law enforcement use of hate crime, while mixed, has been at historically low levels until recently. Regression analyses of hate crime in Los Angeles neighborhoods demonstrate the distinctive relationships between hate crime and changing racial composition and economic characteristics in Los Angeles neighborhoods when compared to other cities covered in the scholarly literature. My analysis of anti-black hate crime across Los Angeles from 2003-2014 provides evidence in favor of the argument that demographic change and economic inequality increase police reported hate crime. There are nuances to these relationships: neighborhoods with more black households moving into areas that are predominantly Latino or white neighborhood are associated with more hate crime, but only at certain tipping points for the percentage of households that are Latino or white. Income inequality makes a strong difference at moderately high levels, but models predict low numbers of anti-black hate crime at low inequality and very high inequality.

Though cohesion is frequently referenced as an important construct of group process in gang scholarship, little is known of the stability of this process over time. The present paper utilizes data from the Hollenbeck Community Policing Area of Los Angeles to examine patterns of association within and between street gangs, focusing on temporal trends in cohesion. Findings indicate that gangs with high cohesion at the beginning of the period studied maintain high levels of cohesion, gangs with mid levels of cohesion experience an increase in cohesion, and gangs of low cohesion present variability in cohesion levels over time. Findings provide support for both the efficacy and potential detrimental effects of civil gang injunctions, relating to the level of cohesion shown in the gang prior to its enjoinment. Areas of future study and policy implications are discussed.

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