The 13 people whose bodies were found in a clandestine grave in the city of Tlalmanalco have all been identified and their remains turned over to Mexico City prosecutors so the investigation can be continued, the federal Attorney General's Office said.

The victims were abducted from a Mexico City bar on May 26 and their bodies were found last week on the La Mesa ranch in Tlalmanalco.

The young people were snatched from the Heaven bar in Mexico City's upscale Zona Rosa district.

Officials "decided to hand over the human remains and all related evidence to the Federal District Attorney's Office with the goal of having it continue the investigation for kidnapping and murder, which are under the jurisdiction of local authorities," the AG's office said in a statement.

Federal crime scene investigators removed the bodies from the site and oversaw identification "via the necessary scientific processes, based on specific forensic DNA techniques, as well as indubitable individual information" provided by Mexico City prosecutors, the AG's office said.

Federal authorities found the mass grave - covered with cement, asbestos and lime - during an unrelated firearms investigation.

Seven people are in custody in connection with the mass abduction and murders, officials said earlier this week.

The mass abduction and murder was carried out in reprisal for the May 24 killing of Horacio Vite Angel, a reputed member of the La Union de Insurgentes drug gang, by the rival La Union de Tepito group, officials said.

One of the people taken from the bar and killed, 16-year-old Jerzy Ortiz, was the son of Jorge "El Tanque" Ortiz Reyes, the jailed boss of La Union de Tepito, officials said earlier. EFE