Early Identification of Violent Criminal Gang Members

Gang violence is a major problem in the United States accounting for a large fraction of homicides and other violent crime. In this paper, we study the problem of early identification of violent gang members. Our approach relies on modified centrality measures that take into account additional data of the individuals in the social network of co-arrestees which together with other arrest metadata provide a rich set of features for a classification algorithm. We show our approach obtains high precision and recall (0.89 and 0.78 respectively) in the case where the entire network is known and out-performs current approaches used by law-enforcement to the problem in the case where the network is discovered overtime by virtue of new arrests - mimicking real-world law-enforcement operations. Operational issues are also discussed as we are preparing to leverage this method in an operational environment.Comment: SIGKDD 201

Cognitive and emotional stressors of child homicide investigations on UK and Danish police investigators

In a previous paper, key differences in the form and manifestation of cognitive and emotional stress experienced by investigators of adult and child homicide were identified, along with a cursory look at how investigators commonly deal or cope with these effects. In this paper, the findings from eleven interviews with UK and Danish police officers with experience of investigating both adult and child homicides, suggest that child homicide investigations can have a profoundly different effect on police investigators that can vary between officers. The effects experienced and coping strategies employed were similar among officers in Denmark and the UK, and these included becoming more emotionally closed and engaging in regular sport and exercise. The findings hold important implications for police training and for the welfare of current and future police homicide investigators particularly where the victim is a child

Where bias begins: a snapshot of police officers’ beliefs about factors that influence the investigative interview with suspects

The aim of the current study was to obtain a snapshot of police officer’s beliefs about factors that may influence the outcome of the investigative interview with suspects. We created a 26-item survey that contained statements around three specific themes: best interview practices, confessions and interviewee vulnerabilities. Police officers (N = 101) reported their beliefs on each topic by indicating the level of agreement or disagreement with each statement. The findings indicated that this sample of officers held beliefs that were mostly consistent with the literature. However, many officers also responded in the mid-range (neither agree nor disagree) which may indicate they are open to developing literature-consistent beliefs of the topics. Understanding what officers believe about factors within the investigative interview may have implications for future training. It may also help explain why some officers do not consistently apply best practices (i.e. strong counterfactual beliefs) versus officers who reliably apply literature-consistent practices to their interviews (i.e. knowledge-consistent beliefs).This research is supported by a fellowship awarded from the Erasmus Mundus Joint Doctorate Program, The House of Legal Psychology (EMJD-LP) with Framework Partnership Agreement (FPA) 2013-0036 and Specific Grant Agreement (SGA) 2015-1610 awarded to Nicole Adams.Published onlin

Hunting patterns and geographic profiling of white shark predation

Predators can play important roles in structuring their communities through top‐down effects on the distribution and abundance of their prey. Sharks are top predators in many marine communities, yet few studies have quantified those factors influencing their distribution and hunting behaviour. Here, we use location data from 340 predatory interactions between white sharks Carcharodon carcharias (Linnaeus), and Cape fur seals Arctocephalus pusillus pusillus (Schreber), data on associated environmental factors, and spatial analysis, including a novel application of geographic profiling – a tool originally developed to analyse serial crime – to investigate spatial patterns of shark attack and search behaviour at Seal Island in False Bay, South Africa. We found that spatial patterns of shark predation at this site are nonrandom. Sharks appear to possess a well‐defined search base or anchor point, located 100 m seaward of the seal's primary island entry–exit point. This location is not where chances of intercepting seals are greatest and we propose it may represent a balance among prey detection, capture rates, and competition. Smaller sharks exhibit more dispersed prey search patterns and have lower predatory success rates than larger conspecifics, suggesting possible refinement of hunting strategy with experience or competitive exclusion of smaller sharks from the most profitable hunting locations. As many of the features of this system will be common to other instances of foraging, our conclusions and approach employed may have implications and applications for understanding how large predators hunt and for studying other predator–prey systems

It's no riddle, choose the middle: the effect of number of crimes and topographical detail on police officer predictions of serial burglars' home locations.

This study examines the effect of the number of crimes and topographical detail on police officer predictions of serial burglars’ home locations. Officers are given 36 maps depicting three, five, or seven crime sites and topographical or no topographical details. They are asked to predict, by marking an X on the map, where they thought each burglar lived. After making their predictions on half of the maps, officers randomly receive either no training or training in one of two simple decision-making strategies. The accuracy of predictions at baseline and retest is measured as the distance between the predicted and actual home locations, and these accuracy scores are compared to a commonly used geographic profiling system. Results show that training significantly improved predictive accuracy, regardless of the number of crime locations or topographical detail presented. In addition, trained participants are as accurate as the geographic profiling system