Spillovers in Criminal Networks: Evidence from Co-Offender Deaths

We study spillover effects within criminal networks by leveraging the deaths of co-offenders as a source of causal identification. We find that the death of a co-offender significantly reduces the criminal activities of other network members. These spillover effects display a decaying pattern: offenders directly linked to a deceased co-offender experience the most significant impact, followed by those two steps away, and then those three steps away. Moreover, we find that the death of a more central co-offender leads to a larger reduction in aggregate crime, underlining the importance of network position in shaping spillover effects. We also provide evidence suggesting that the loss of a co-offender shrinks the future information set of offenders, which can influence their perceived probability of being convicted and consequently their criminal behaviour. Our findings highlight the importance of accounting for spillover effects in designing more effective strategies for crime prevention.