Raul Benitez, a security expert at the National Autonomous University of Mexico, says that the spate of recent deaths may be no coincidence: It comes as the federal government is increasing intelligence capabilities and taking a harder look at collusion between traffickers and local police and authorities, as it looks to centralize the police force. Therefore, many mayors who once may have turned a blind eye to trafficking exploits in their towns might now be refusing to cooperate. “If the mayor is an obstacle, that is when the problem starts,” says Mr. Benitez.