MEXICO CITY (AP) _ Authorities filed murder indictments against three people Saturday in connection with 15 slayings in Matamoros blamed on a cult of devil-worshippin g narcotics traffickers.

Sara Aldrete Villarreal, a 24-year-old Matamoros college student authorities call the cult's high priestess, Omar Francisco Orea Ochoa, 23, and Alvaro de Leon Valdez, 22, pleaded innocent.

Aldrete was a companion of cult ''godfather'' Adolfo de Jesus Constanzo and Orea Ochoa was one of several of Constanzo's homosexual lovers who belonged to the cult. De Leon Valdez served as Constanzo's bodyguard and, authorities say, his executioner in a death pact.

The indictments also include weapons, drug and criminal association charges, a spokesman for the 9th Federal Criminal Court in Mexico City, Hector Miranda, said.

The three suspects were indicted last month in two other slayings, the May 6 shootings deaths of Constanzo and his right-hand man, Martin Quintana Rodriguez. Constanzo and Quintana died when police closed in on the Mexico City apartment where they had been hiding out.

Constanzo, Quintana, Aldrete, Orea Ochoa and de Leon Valdez went into hiding in early April after police in the border town of Matamoros discovered 15 horribly mutilated bodies buried on two ranches.

At least four were the victims of bizarre ritual sacrifices that both authorities and suspects say were aimed at invoking magical protection for drug-smuggling.

A 21-year-old University of Texas pre-med student kidnapped while on spring vacation, Mark Kilroy, was among the sacrificial victims.

Seven people in Matamoros, including two fugitives, were charged last month in the slayings.

Aldrete and Orea Ochoa, of Mexico City, told The Associated Press in a prison interview Friday that Constanzo forced them to go into hiding with him. They both said they knew nothing about the slayings until they saw news reports on television. Aldrete also rejected the allegation she was the cult's high priestess or ''godmother.''