Colombian authorities intensified the search for seven of eight mayors still missing after having been kidnaped over the weekend by a leftist rebel group. "We are not sure what the guerrillas are up to," said a Ministry of Defense spokesman, Col. Victor Arevalo. "It is definitely part of their new offensive to destabilize oil production. And (Monday) is also the anniversary of Camilo Torres." Torres, a Roman Catholic priest who in 1966 joined the rebels of the National Liberation Army, was killed by Colombian troops 21 years ago in the oil-rich northeast region where the mayors were kidnaped. The eighth kidnap victim, Daniel Palacios of Morales, was released by the rebels.