Six employees of the Mexican Attorney General's Office have been killed in a plane crash, authorities say.
And a newspaper said an auditors' report indicated months ago that the aircraft fleet for prosecutors was in poor condition.
Attorney General Jesus Murillo Karam said the cause of the crash in northern Zacatecas state is being investigated.
The officials had flown to Zacatecas to serve an arrest warrant on members of the Zetas drug cartel.
Mr Murillo Karam said their small, twin-engine propeller plane was about 28 years old.
The newspaper El Universal said today that an auditors' report issued in October found serious problems with maintenance and airworthiness in the prosecutors' fleet of aircraft.