ACAPULCO, Mexico - The body of a Mexican army captain was found in southern Guerrero state yesterday, a day after a severed head was left outside a military base with a note suggesting criminal gangs would defy the army's increased presence.

Also in Guerrero, unidentified attackers tossed a grenade late Saturday at a police station in the city of Tecpan, damaging two police cars but causing no injuries.

Police found Capt. Jacinto Pablo Granda, 36, near a highway in Guerrero's capital of Chilpancingo, 60 miles north of Acapulco, with two gunshot wounds to the head, said Erit Montufar, state director of investigative police.

Granda was vacationing with his family when he was abducted Saturday by armed men near a Chilpancingo military base, Montufar said.

On Saturday, the head of a kidnapped auto mechanic was left in a box along with two grenades and a note from the purported gang members outside a military barracks in the Gulf coast city of Veracruz.