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.