This brief fills a gap in the studies of organized crime in Mexico (Kan 2012, Rios 2011, Dell 2011) by documenting and mapping the post-2008 assassination of Mexican border police chiefs. It traces out a systematic of law-enforcement assassination in Northern Tier Mexico, showing how the selective, often sequential, hits by cartels on chiefs in border towns and along key drug-trafficking corridors has proven an effective strategy by organized crime elements to serve several goals: (1) to retaliate for federal, state and local prosecution, (2) to try and neutralize police chiefs, (3) to...