The number of corpses found in clandestine mass graves located in Mexico's western state of Jalisco has increased to 55, Jalisco's Attorney General Luis Carlos Najera said Wednesday. The authorities began early this month to dig up the graves in the towns of Vista Hermosa, in Michoacan state, and La Barca, in Jalisco state, both located in western Mexico. At a press conference held in Guadalajara, capital of Jalisco, Najera said two more bodies were found in recent hours, but did not mention exactly where they were found. The authorities now have clues that may lead to those responsible for the killings and mass burials, Najera told reporters. The mass graves were found when the Mexican Army and local, state and federal police departments searched for two police officers involved in a federal investigation after they were reported missing. The Federal Agency for the Investigation of Organized Crime (SIEDO), which is heading the search, said the bodies of the two federal investigators have not been found. Up to now, the Federal Attorney General's Office has not confirmed the identities of the bodies and the reasons for the killings.