MEXICO CITY – Gunmen have abducted the chief of kidnapping and organized crime investigations for the Mexican border state of Coahuila, authorities said Thursday.

The Coahuila prosecutor's office said in a statement that commander Gerardo Valdes was seized Monday by at least six men as he was driving in the state capital, Saltillo.

The office said an unidentified man called police a few hours later and said he had been kidnapped by the Juarez drug cartel.

Also Thursday, a policeman was found tortured and shot to death in Ciudad Obregon in the state of Sonora, across the border from Arizona.

The state's public safety department said Jose Valle's right index finger had been cut off and stuffed in his mouth, a common punishment dealt out by drug traffickers to informers, and that his head was almost completely detached.

President Felipe Calderón has deployed 25,000 soldiers across the country to battle drug gangs, which have responded with bold attacks on the military and police. More than 4,000 people have been killed in turf wars, assassinations and shootouts since 2005.