Four police officers were killed Saturday while attempting to remove a powerful bomb allegedly planted by leftist rebels as part of an attempt to kill a city mayor, authorities said. Police officers found the explosive before dawn Saturday hidden in a water meter in front of the radio station where on Thursday a car bomb nearly claimed the life of the pro-government mayor of Neiva, Cielo Gonzalez. Police removed the bomb and were transporting it in a police vehicle when it exploded in downtown Neiva, killing four officers, police spokesman Sgt. Alberto Cantillo told The Associated Press. Among the dead was Capt. Carlos Cardona, local head of the Sijin police intelligence unit. Gen. Jorge Castro, chief of Colombia's police, told Caracol Radio that the device was part of Thursday's failed attack against Gonzalez by the Revolutionary Armed Forces of Colombia, Latin America's oldest and most potent leftist insurgency.