LOS ANGELES (AP) — Six people were charged Tuesday with running a Mexico-based kidnapping ring that took nine people hostage and demanded ransom from their U.S. relatives but killed six of them, including some after the money was paid, officials said.

A federal grand jury in Los Angeles charged the alleged ringleader, German Garcia Yera Hernandez, 37, and five others with crimes including extortion and conspiracy to commit hostage taking resulting in death, according to a statement from the U.S. attorney’s office in Los Angeles.

All six were being held in Mexico, where they face additional charges, and it wasn’t immediately clear whether they had attorneys to speak on their behalf.

The indictment alleges that from January to April of last year, the Tijuana-based gang took people for ransom in Mexico by luring them into meetings where they were taken hostage at gunpoint, tied up and sometimes badly beaten.

Family members in the U.S. were then called for ransom. Some who didn’t have family members who could pay were killed and some hostages were killed to protect the conspiracy even after being ransomed, according to the U.S. attorney’s office’s statement.

Six people were killed, including three U.S. citizens, authorities said.

In one case, two people from the U.S. and Mexico were abducted after meeting one of the kidnappers at a Tijuana nightclub and being invited to a home, according to the indictment.

They were beaten and killed after the kidnappers learned that they had no money, the indictment said.

Another man was killed even though his adult son left a $25,000 ransom payment that was collected in the women’s restroom of a McDonald’s restaurant in San Ysidro, a San Diego neighborhood near the border, according to the indictment.

In another case, a U.S. national living in the Los Angeles suburb of Norwalk was kidnapped while visiting a relative in Tijuana.

The victim “was forced to call his mother, say he was in trouble and instruct her to call an individual to pay $25,000 for his release. The victim’s mother struggled to obtain the ransom money but agreed to pay the hostage takers $1,000″ along with the man’s car for his release, according to the U.S. attorney’s office.

But the man was killed on the same day his mother met with the ransom collector in Norwalk, the indictment alleged.

If convicted, the six defendants could face the death penalty or life in prison without chance of parole.