The Mexican Navy says tests confirm that a man killed in a shootout with marines was Heriberto Lazcano, the head of Los Zetas drug cartel. Officials said comparisons with fingerprints held on their database showed it was the drug boss. In a reference to reports that the body was missing, they said the body had been given to local authorities. Lazcano is a founder of Los Zetas which has been implicated in a string of mass killings and kidnappings. His death would be a victory in the fight against cartels, analysts say. Lazcano was killed on Sunday in the northern state of Coahuila but his identity had not been confirmed until now. The Navy said that fingerprints taken from the body were compared with those on their database, confirming that it was Lazcano. Also photos of the corpse's face were compared with previous photographs of Lazcano. The Navy said that the body had then been handed over to the local authorities in Coahuila. However, the Mexican media are reporting that Lazcano's body is now missing. The Milenio newspaper said that it seemed alleged family members had reclaimed his corpse, although it said other accounts suggested attackers had broken into the funeral home to steal the body. Mexican police believe a recent surge in mass killings is due to a split within the Zetas cartel. Lazcano was thought to be the leader of one faction, while the other is led by Miguel Angel Trevino Morales. In the nearly six years of Felipe Calderon's presidency, more than 50,000 people are believed to have died in violence blamed on organised crime.