The police chief of Aquismon, a city in the central Mexican state of San Luis Potosi, was murdered by gunmen, prosecutors said.

Adolfo Bueno Bautista was killed on Monday, the San Luis Potosi Attorney General's Office said in a statement.

The police chief and his wife were attacked as they were driving out of the city of Valles toward Tamazunchale, the AG's office said.

Investigators have determined that four gunmen in a white pick-up truck caught up to the police chief's automobile and opened fire, the AG's office said.

Bueno Bautista was pronounced dead at the scene, but his wife was not hurt.

The gunmen drove in the direction of Ciudad Valles after the attack, eyewitnesses said.

Investigators found 14 7.62 mm bullet casings from AK-47 assault rifles at the crime scene, the AG's office said.

State and municipal police launched an operation to find the gunmen, the AG's office said.

The investigation is ongoing and officials plan "to review the security cameras in the city," the AG's office said. EFE