LAPD officer Fernando Arroyos was shot dead on Monday while off-duty, and federal prosecutors have charged four people in connection to his killing. Prosecutors have alleged the suspects are all tied to a street gang called Florencia 13 (F13).

The incident took place south of Los Angeles County in an unincorporated area, around 9 p.m. on Monday. Officer Fernando Arroyos was at the location looking for houses to buy with his girlfriend when the alleged gang members pulled up in a pick-up truck. Arroyos was targeted because of the two silver chains around his neck, according to the authorities. After getting out of the truck, there was an argument between the suspects and the officer which led to gunfire.

While his girlfriend managed to be unharmed during the exchange, officer Fernando Arroyos was shot once. The alleged gang members are now charged with violent crime in aid of racketeering that they are believed to have committed in furtherance of their gang.

Luis Alfredo De La Rosa Rios, 29, Ernesto Cisneros, 22, and Jesse Contreras, 34 are the three suspects involved in the killing of Fernando Arroyos. They are known as; “Lil J”, “Gonzo” “Skinny Jack” or “Flaco” in their gang, respectively. 18-year-old Haylee Marie Grisham, considered an associate of the gang, is Rios’s girlfriend. There are no comments on behalf of them from their attorneys so far, which is why it is unclear if they have any yet. Their first hearing is on Friday evening in a federal court.

The Florencia 13 is an LA-based Latino street gang from the Florence-Firestone neighborhood of South LA, they were founded in the 1950s according to a federal affidavit. They are allegedly also overseen by the Mexican Mafia, drug trafficking in the area. The affidavit also states that all three suspects told police officers that they are indeed gang members of F13 and all have matching tattoos for it too.

The gunfire was followed after the suspects had robbed a couple of a few of their belongings. After the law enforcers reached the scene of the crime, Fernando Arroyos was rushed to a hospital with his gunshot wound where he was pronounced dead.