MEXICO CITY — A mass grave discovered in the Mexican state of Veracruz contained more than 250 human skulls, most likely the victims of criminal drug cartels, the state’s attorney general said on Tuesday.

“For many years, the drug cartels disappeared people and the authorities were complacent,” Jorge Winckler, the state attorney general, said in a television interview with the Televisa network.

Veracruz, on Mexico’s Gulf coast, has been the epicenter of battles among the country’s drug gangs. The remains found at the site indicated that the victims might have been killed years ago, Mr. Winckler said.

Describing the crime-ridden state as a “giant grave,” Mr. Winckler said the state authorities would match D.N.A. samples at the scene to a database from the relatives of the missing.