BOGOTA, Colombia - Colombian security forces carrying out an arrest warrant Friday for a top rebel leader killed a man in a shootout, and were trying to confirm his identity, an official in the chief prosecutor's office said Friday. The raid targeted Ivan Rios, a member of the FARC guerrillas' ruling junta. If the body is identified as his, it would be the second member of the ruling secretariat of the Revolutionary Armed Forces of Colombia, or FARC, to be killed in a week. That would be a huge blow to Latin America's oldest and strongest insurgency, shaken by the...