LOS ANGELES (AP) — Federal officials say six people have been charged in Los Angeles with running a Mexico-based kidnapping ring that took nine people hostage and demanded ransom from their U.S. relatives but killed six of the victims.

A federal grand jury indicted them on Tuesday.

The U.S. attorney's office in Los Angeles says in a statement that the Tijuana-based ring took people for ransom in Mexico last year by luring them into meetings where they were taken hostage at gunpoint.

Family members in the U.S. were then called for ransom.

Authorities say six of the victims including three U.S. citizens were killed. Some were killed after the ransom had been paid.