Three dead bodies were found Tuesday hanging from pedestrian bridges in the central Mexican city of Cuernavaca.
Morelos state prosecutors' spokesman Efrain Vega said the victims were shot to death. The bodies were accompanied by threatening notes signed by a drug gang.
Vega said the three men escaped from a state prison last month.
The message accused them of working for Edgar Valdez Villarreal, a U.S.-born enforcer known as "La Barbie." It was attributed to the Southern Pacific cartel, believed to have formed from the remnants of the Beltran Leyva cartel.
Authorities say more than 120 people have died this year in a turf war between Valdez Villareal and Hector Beltran Leyva.
Also Tuesday, gunmen killed three state police officers in two ambush-style attacks in the border city of Ciudad Juarez. Another officer was seriously wounded.
Arturo Sandoval, a spokesman for prosecutors in the northern state of Chihuahua, where Ciudad Juarez is located, said the first attack occurred on a busy avenue, killing both agents in a patrol vehicle; a second patrol car was attacked 15 minutes later elsewhere on the same avenue, killing one officer and wounding another.
Ciudad Juarez has been hit by over 1,400 drug-related killings so far in 2010, and over 2,600 in 2009. There was no immediate information on the identity of the assailants or motive in the Tuesday attack.
Also Tuesday, Mexico's Defense Department reported that three assailants died Monday in a shootout with soldiers in the border city of Reynosa. The soldiers reportedly came under fire while on patrol, returned fire and seized three rifles at the scene.