A police officer, shot dead on Monday, became the ninth victim in January in the fight against drug trafficking in the northern Mexican state of Nuevo Leon, authorities said.
The killings took place as the Mexican government is ratcheting up its crackdown on drug trafficking and other organized crimes in the northern and southern states of Mexico.
Javier Trevino Rodriguez was gunned down by machine gun fire in his van on Monday morning in San Pedro Garza Garcia, a municipality in the outskirts of Monterrey, the state capital.
Two killers opened fire as they drove by. They managed to escape.
Multiple gun wounds were found on his head and back, and there were at least 21 bullet holes on the van.
His car went out of control and plunged into the nearby Santa Catarina River.
President Felipe Calderon's government has sent thousands of troops to join law enforcement officers to fight drug trafficking and other organized crimes, which he promised to undertake while taking office in December.
The country saw 2,221 murders related to drug trafficking in 2006, the highest number in six years.