Why police should treat gun homicide like doctors treat bloodborne pathogens

By studying gun violence like we study disease, the police can improve the chances of discovering who has a greater chance of being shot

This article is based on research conducted as a part of the CA POST Command College. It is a futures study of a particular emerging issue of relevance to law enforcement. Its purpose is not to predict the future; rather, to project a variety of possible scenarios useful for planning and action in anticipation of the emerging landscape facing policing organizations.

The article was created using the futures forecasting process of Command College and its outcomes. Managing the future means influencing it – creating, constraining and adapting to emerging trends and events in a way that optimizes the opportunities and minimizes the threats of relevance to the profession.

The United States is suffering from a deadly public health crisis – gun violence. As we emerge from the current once-in-a-lifetime COVID-19 pandemic and make advancements in COVID-19 vaccinations, what lessons might we learn from the epidemiology of contagious diseases and evidence-based medicine to combat gun violence as a public health contagion?

President Biden recently suggested in a press conference that this health crisis is based on the proliferation of gun purchases and the emerging popularity of ghost guns. (The chart below shows firearms and ghost gun recoveries for the Vallejo Police Department in California.) Ghost guns are easily manufactured by purchasing polymer 80s or 80% already constructed lower bottom firearms and matching them with upper assembly parts to create a gun without a serial number.

But the reasons for gun violence are rooted in many complex societal concerns. The list of confounding explanations includes poverty and social strain, COVID-19 mask anonymity, a lack of police legitimacy, a significant increase in guns and ghost guns, street gangs, a blatant contempt for police played out for the world to see, de-policing, and a perception by the criminal element that the criminal justice system is closed for business and if prosecuted, seldom done in a swift and certain way with court trials often delayed.

Vallejo PD Ghost Gun Recoveries by epraetorian on Scribd

To address the surge in gun crimes, the police should explore solving gun crime like the medical profession studies how to treat bloodborne pathogens with the intentional targeting of risky behavior within a network.

Evidence-based policing

Evidence-based policing (EBP) aims to inform our decisions based on the best available data, science, analysis and research [1], in a similar way to evidence-based medicine. For example, most of us demand that our doctors are attentive to research and data and that medical services are based on the best science. Using the best available evidence to inform our long-term decisions can help us improve public safety and improve legitimacy while also boosting violent crime reduction. [2] Targeting, testing and tracking our data to ensure our strategies are working is critical to assess our interventions. [1] EBP takes effort and resistance to instant gratification and low-hanging fruit concepts that seem to permeate the profession. Putting cops on dots and deploying patrol officers in the right "dosages," (e.g., patrolling sporadically every two hours in criminal hotspots with timely crime intelligence), has been shown through empirical research to work. [2]

The challenge to move a profession's culture to embrace data-driven strategies instead of ad hoc approaches, though, are immense. If Oakland A's General Manager Billy Beane can face resistance embracing data and analysis in professional baseball (despite being widely successful), then we should not be surprised that policing still emphasizes experience and tradition while viewing evidence-based approaches that focus on data and research with skepticism. [3] The police tend to dismiss science, research and data regarding policing (understandably so) when they intersect with life and death decisions that have dynamic demands, interactive complexity and shifting responsibilities for law enforcement. [4]

Study gun violence like we study disease

By studying gun violence like we study disease, the police can improve the chances of discovering who has a greater chance of being shot. The likely result is transitioning to resources to police better, more innovatively and more fairly.

The concept is straightforward. A powerful analogy drives home this point – treat gun homicide like a bloodborne pathogen, something transmitted from person to person through specific risky behaviors. Put another way; gun violence is not an airborne pathogen subject to randomness. In short, "You don't catch a bullet like you catch a cold." [5]

We must explore the importance of leveraging technology while co-producing policing and building trust with street outreach workers to identify influencers, including improving systems in police organizations that provide the correct treatment – all in an era of doing more with less, a tall task. One solution is to couple social network and shell casing analysis.

Social Network Analysis (SNA) 

Social network analysis (SNA) examines past killings and shootings. A simple explanation for SNA suggests starting with a homicide victim and identifying all those they were criminally connected to, then proceeding to the next victim and repeating the process to generate a report for the highest risk for violence. The more connections in the network, the higher the risk of being a victim of violence. [6] SNA also identifies influential individuals based on their social position and ability to influence and connect with criminal networks involved in gun violence. [7]

If implemented effectively and with new robust police records management systems that easily incorporate SNA, law enforcement can be much more intentional in targeting the influencers of violent crime. Officers can precisely focus on the hidden influencers and information brokers. Once identified, municipalities might be served well to disrupt and intersect those criminal networks with street intermediaries. [8] This intentionality may positively impact communities by building legitimacy collectively with street outreach workers and reducing harm through precise data-driven approaches. [9] 

Approaches that utilize SNA coupled with National Integrated Ballistic Information Network (NIBIN) may identify connections between shell casings to determine when violent offenders used the same gun in multiple incidents. [10] All this is accomplished through specific tool mark strikes, transferred to cartridge cases – similar to fingerprints. When there is a connection between the shell casings, there is an association between two or more gun-fired incidents and those associated individuals. [10] SNA then provides police with the ability to understand the distribution of violence better and to identify individuals who are likely to become victims or perpetrators of violent crime based upon their connections and previous criminal history.

Research has found evidence for a victim-offender overlap, indicating perpetrators of violence have a higher likelihood of being a victim and vice versa. [11] Thus, a perplexing question: why isn't social network and NIBIN analysis more common? As a profession, the police would be inept if we didn't send fingerprints to AFIS and DNA to CODIS. Why not shell casings to NIBIN? Investigators could also couple NIBIN and SNA analysis with evidence-based strategies to combat gun violence with data-driven strategies to identify those hot people and hot places. [12] 

By continually analyzing and assessing data, we can better understand the impact of our responses to gun crime, using NIBIN and SNA to identify the main influencers of gun crime, and utilizing geographic information systems (GIS) to identify hotspots that enable police leaders to put "cops on dots" – research shows it works. [12] 


Most of what has already been discussed requires resources. As a profession, the police must depend on funding from the Commission on the Accreditation for Law Enforcement Agencies (CALEA), the Department of Justice, and our state Peace Officer Standards and Training organizations to provide regional law enforcement technology support for cash-strapped organizations. Despite funding difficulties, there are several ways the police can become more data-driven, evidence-based and effective while striving to improve clearance rates:

  • Improve systems and subsystems that align contemporary policing to combat violent crime in a fair, equitable manner and that restores trust, confidence and legitimacy. To improve legitimacy, readjust and balance patrol deployments for prevention and problem solving that are precise and don't cast wide nets. [9, 13, 14]
  • Utilize precision-based analysis to combat the 20% of people that account for almost 80% of all crime. [15]
  • Utilize social network analysis, NIBIN, GIS and auditory detection technology to collect shell casings, cloud-based records management systems and cloud-based computing to provide actionable data on criminal influencers and information brokers in any criminal network.
  • Utilize SNA to focus and identify those most influential violent offenders in a network, and with that information, work with street intermediaries to combat violence. [8, 10, 16]
  • Consider innovative hotspot policing approaches based on evidence-based policing. Police departments can have a residual impact on crime if they patrol sporadically in hotspots every two hours in only 10- to 16-minute increments with timely intelligence. [2]
  • Measure outcomes such as crime reduction instead of outputs such as arrests, citations and prosecutions, to test and compare interventions to see if they are having an impact.
  • Target the most significant drivers and people involved in gun violence, along with the consistent and standard prosecution for the eradication of "ghost guns" in the hands of prohibited persons.
  • Target people, places and behavior with prevention, intervention and enforcement strategies that consider wrap-around services such as cognitive behavioral therapy, a form of psychological treatment that addresses problem thinking and behavior. [6-7]

Future scenario

Let us see how using data to attack crime might look like in 2028.

Keywords based on algorithms have alerted the police department's real-time intelligence center and its cadre of crime analysts and civilian specialists concerning a dispute played out on social media between two figures in a violent social network. In 2021, many shootings occurred based on social media disputes, and in 2028, it is no different.

Based on the information, detectives file for a tracking warrant. They track one of the instigators by not only his phone but also his various smart devices. The system determines his stress levels based on biometric data, indicating a violent confrontation might be imminent. Police are dispatched to prevent it before it begins with the exponential growth of increased surveillance, auditory detection, and drones used effectively together as a tool in policing.

The system has also discovered through NIBIN and SNA the guns registered to these offenders are used in previous shootings. Utilizing computer vision cameras, UAS (drones), machine learning/artificial intelligence and auditory detection, police sift through surveillance footage but do so efficiently with sophisticated video management analytics that quickly filters descriptions. They now know what car the offender drives, where he lays his head, who his girlfriend is, all in a matter of minutes.

Believing that a violent confrontation is likely, they deploy a UAS/drone that hovers overhead and monitors the offender. As he leaves his home, the drone alerts an officer nearby, who then deploys a less-lethal device that immediately incapacitates him but does so without killing him. Officers locate an old ghost gun firearm in his pocket; something society still has trouble eradicating in 2028. 


Today, we already have many of the solutions we will employ in the future but we must endeavor to safeguard civil liberties and privacy while implementing them. Reducing harm while being precise in our approaches should also be at the forefront of everything we do. As a profession, the police must lean into precise data-driven strategies that build legitimacy by assessing objective data, and that focus on the victim and those areas plagued by violence, e.g., 3%-5% of any city area can account for 50%-60% of all crime. [14, 17] In addition to policing violent places, the profession would be served well to invest in those disenfranchised communities. This approach is most effective when focus and fairness are paired with balance, which is fundamental to combating place-based gun violence. Other attributes of successful anti-violence efforts include coupling "punishment with prevention, sanctions with rewards and immediacy with sustainability." [7]

Additionally, we must bake harm reduction and precision-based policing into all our systems and subsystems – not in a temporary solution but a sustainable one. [18] The analogy of fishing with a spear instead of casting a wide net, many would assert, is more accurate today than ever. With these specific approaches, police can utilize SNA and trend analysis to identify potential information brokers and hidden influencers. To do this, police must look at those involved in the NIBIN leads and identify other incidents they might be involved. This method further builds out the social networks of those involved in shooting incidents, disrupting community violence or the next shooting. 

Wayne Gretzky was great because he skated to where he anticipated the puck to go, not where it was. Police leaders must anticipate and strive to be forward-thinking. Using the best available data, science and research to inform our decisions will improve our police strategies to combat violent crime and, in particular, gun violence. The challenges are immense. Police leaders of course must answer to the police, the community, and local politicians – each with their concerns. With hiring, staffing and retention concerns, the challenges are further exacerbated. To that end, though, we must find innovative ways to effectively leverage technology and utilize evidence-informed strategies to treat this public health crisis, one which deserves our immediate attention.


1. Sherman LW. (2013). The rise of evidence-based policing: Targeting, testing, and tracking. Crime and justice, 42(1), 377-451.

2. Lum CM, Koper CS. (2017). Evidence-based policing: Translating research into practice. Oxford, UK: Oxford University Press.

3. Worden RE, McLean SJ. (2017). Research on police legitimacy: The state of the art. Policing: an international journal.

4. Weisburd D, Neyroud P. (2011). Police Science: Toward a New Paradigm. Annotation.

5. Papachristos A. (2013). Social network analysis can help predict gun violence. Washington Post.

6. Abt T. (2019). Bleeding out: The devastating consequences of urban violence--and a bold new plan for peace in the streets. Basic Books.

7. Papachristos AV, Braga AA, Hureau DM. (2012). Social networks and the risk of gunshot injury. Journal of Urban Health, 89(6), 992-1003.

8. Advance Peace (2020).

9. Bratton William J, Murad J. How Precision Policing Made New York Even Safer. New York Post, July 29, 2018. Precision Policing: A Strategy for the Challenges of 21st Century Law Enforcement. In Urban Policy 2018. New York: Manhattan Institute for Policy Research, 2018.

10. Gill L, Fox A (2018). Using NIBIN and Social Network Analysis to understand the world of violence in King County, Washington. Unpublished document.

11. Jennings WG, Piquero AR, Reingle JM. (2012). On the overlap between victimization and offending: A review of the literature. Aggression and Violent Behavior, 17(1), 16– 26.

12. Sherman LW, Gartin PR, Buerger ME. (1989). Hot spots of predatory crime: Routine activities and the criminology of place. Criminology, 27(1), 27-56.

13. Clarke RV, Eck JE. (2005). Crime analysis for problem solvers. Washington, DC: Center for Problem-Oriented Policing.

14. Nagin DS. (2013). Deterrence in the twenty-first century. Crime and justice, 42(1), 199-263.

15. Martinez NN, Lee Y, Eck JE, SooHyun O. (2017). Ravenous wolves revisited: A systematic review of offending concentration. Crime Science, 6(1), 1-16.

16. Coburn J (2020). Produced by the Center for Global Healthy Cities

17. Kennedy DM. (1996). Pulling levers: Chronic offenders, high-crime settings, and a theory of prevention. Valparaiso University Law Review, (Issue 2), 449

18. Ashraf MJ. (2020). Precision Policing: A Way Forward to Reduce Crime (Doctoral dissertation, Monterey, CA; Naval Postgraduate School).

Additional resources

Carey B. (2020). Mapping the Social Network of Coronavirus. New York Times. 

CDC. (2020), Firearm Violence Prevention.

FBI UCR, 2019.

Harari Y. (2020, June 18). Congratulations. You Are Now Hackable Humans [Video]. YouTube.

Harari YN. (2020). The world after coronavirus. Financial Times.

King W, Wells W, Katz C, Maguire E, Frank J. (2013). Opening the black box of NIBIN: A descriptive process and outcome evaluation of the use of NIBIN and its effects on criminal investigations. Final report NC [243875], National Criminal Justice Reference System, USA.

McNeil D (2020). Can Smart Thermometers Track the Spread of the Coronavirus? New York Times.

Morselli C. (2010). Assessing vulnerable and strategic positions in a criminal network. Journal of Contemporary Criminal Justice, 26(4), 382-392.

Ratcliffe JH. (2015). Towards an index for harm-focused policing. Policing: a journal of policy and practice, 9(2), 164-182.

Reese T. (2020). California Health Line

Roig E, Olson R. (2020). A public health intervention for violence across the Americas. The Hill. 

Sherman LW. (2011). Al Capone, the sword of Damocles, and the police-corrections budget ratio. Criminology & Pub. Pol'y, 10, 195.

Vallejo PD Crime Analyst (2021). Data Evaluation of Ghost Guns Recovered in the City of Vallejo. (August 25, 2021).

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