LOS ANGELES (CNS) — A federal grand jury Thursday returned an indictment against three gang members and one associate for the fatal shooting of an off-duty Los Angeles Police Department officer.

The three men and the 18-year-old girlfriend of one defendant were charged with violating a federal racketeering statute for their roles in the robbery and fatal shooting of Los Angeles Police Department Officer Fernando Arroyos on Jan. 10, according to the U.S. Attorney's Office.

The charge of violent crime in aid of racketeering carries a potential death penalty and a minimum sentence of life in federal prison without the possibility of parole because the fatal shooting occurred during a robbery, prosecutors said.

Charged with violent crime in aid of racketeering to increase and maintain position within the Latino gang based in South Los Angeles were:

• Luis Alfredo De La Rosa "Lil J" Rios, 29;
• Ernesto "Gonzo" Cisneros, 22;
• Jesse "Skinny Jack" Contreras, 34; and
• Haylee Marie Grisham, 18, Rios' girlfriend.

Rios and Contreras are set to be arraigned on Feb. 3, Grisham on Feb. 7 and Cisneros on Feb. 10 in Los Angeles federal court.

Los Angeles County Sheriff Alex Villanueva indicated he directed detectives to take the case to the U.S. Attorney's Office because of his opposition to District Attorney George Gascón's decision to no longer pursue sentencing enhancements in gang cases.

Those enhancements in a murder case can mean the difference between a life term with the possibility of parole and never being released from prison.

The shooting occurred about 9:15 p.m. Jan. 10 in the 8700 block of Beach Street, near Firestone Boulevard, in the unincorporated Firestone-Florence area, authorities said.

According to a complaint filed Jan. 13 by FBI Special Agent Seamus Kane, Rios admitted in an interview with sheriff's detectives his involvement in the killing, saying he and the other defendants were driving around looking to "make money," which he further explained meant to rob a person of property or money.

Federal prosecutors allege that Rios and Cisneros exited a black pickup and confronted Arroyos, a three-year veteran of the LAPD, and his girlfriend as they were searching for a home to purchase in the area.

The two allegedly pointed guns at the victims and removed property from both, including a wallet and two silver chains from Arroyos' neck, said sheriff's Capt. Joe Mendoza.

"At some point after Cisneros removed (Arroyos') chains, (Arroyos) and the two suspects exchanged gunfire," according to court documents.

Arroyos sustained a single gunshot wound, ran from the area and collapsed in an alley as the suspects fled the scene in the truck.

Responding sheriff's deputies arrived at the scene and found bystanders performing CPR on Arroyos, Mendoza said. The deputies loaded Arroyos into a patrol car and took him to a hospital, where he was pronounced dead. 

Detectives retrieved a loaded handgun from the scene belonging to one of the suspects, and the sheriff's department received a report about 9:25 p.m. Monday of a man suffering a gunshot wound in the area of Junction Street and East 60th Street about a mile-and-a-half from the site of the shooting, Mendoza said.

Investigators later determined the wounded man was Cisneros, and he had sustained the gunshot during the shootout with Arroyos. Contreras was also found in the area hiding inside the garage of his residence in the 5900 block of Junction Street.

A second handgun was retrieved from Contreras' residence and will be tested to determine if it was used in the shooting, Mendoza said.

Rios and Grisham were later found and taken into custody at their residence.