Authorities in the Mexican state of Jalisco have disarmed police in two towns in the area where a military helicopter was shot down during an operation against the Jalisco New Generation drug cartel. Eight people on the aircraft died.

Jalisco Gov. Aristotle Sandoval says in a statement that 150 state police officers performed the "preventative disarmament" of the 19 local police officers in Villa Purificacion and the 11 officers in Union de Tula on Friday.

He says an investigation after the helicopter's May 1 downing found evidence the two police forces had been infiltrated by organized crime.

The attack on the helicopter by a convoy of suspected cartel gunmen came during an operation aimed at Jalisco New Generation, which has emerged as one of Mexico's stronger and most aggressive cartels.