The defendants -- Luis Alfredo de la Rosa Rios, 30; Ernesto Cisneros, 25; and Jesse Contreras, 36 -- each pleaded guilty in July 2023 to one count of conspiracy to violate the Racketeer Influenced and Corrupt Organizations Act, according to the U.S. Department of Justice.
Rios and Cisneros were both sentenced Friday in a packed federal courtroom in downtown Los Angeles to 50 years in prison, while Contreras received 35 years.
A fourth defendant, Haylee Marie Grisham, 21, a gang associate who was Rios' girlfriend, pleaded guilty last year to one count of violent crime in aid of racketeering for participating in the fatal robbery of Arroyos. She is scheduled to be sentenced on Sept. 9.
"No one is immune from the impact of gun violence," U.S. District Judge Percy Anderson said during the nearly four-hour sentencing hearing.
"... Gun violence can strike wherever you are, even in Butler, Pennsylvania," he said, referring to the scene of the attempted assassination of Republican presidential candidate and former President Donald Trump.
RELATED: Fernando Arroyos, LAPD officer killed while house-hunting with girlfriend, honored at somber funeral
On the night of Jan. 10, 2022, the defendants were driving around the Florence-Firestone area of South Los Angeles looking for someone to rob when they came upon Arroyos, who was wearing gold chains around his neck, according to plea agreements filed in Los Angeles federal court.
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. Arroyos, who was 27 and grew up in South Los Angeles, was assigned to the LAPD's Olympic Division.
The two gang members pointed guns at the victims and removed property from both, including a wallet and two silver chains from Arroyos' neck. At some point after Cisneros removed Arroyos' chains, the off-duty officer and the gang members exchanged gunfire, court documents show.
Arroyos sustained a single gunshot wound, ran from the area and collapsed in an alley as the two defendants left the scene in the truck.
Responding law enforcement officers found bystanders performing CPR on Arroyos. The officers loaded Arroyos into a patrol car and took him to a hospital, where he was pronounced dead.
Arroyos' girlfriend, Angela Mendoza, carrying a framed photo of the late officer, spoke to the court Friday with former Los Angeles County Sheriff Alex Villanueva at her side.
"I am reliving the worst day of my life in asking for the maximum (sentence) for these degenerates who took my honey away,'' she said from the podium. "What an exceptional human being was ripped away from us."
Mendoza spoke of Arroyos' sense of humor and singing voice, and thanked Villanueva for bringing the case to federal rather than local prosecutors to ensure more stringent sentencing.
Immediately following the shooting, detectives retrieved a loaded handgun from the scene belonging to one of the suspects, and the Los Angeles County Sheriff's Department received a report of a man suffering from 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.
Investigators later determined the wounded man was Cisneros, who 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, where a second handgun was retrieved.
Rios and Grisham -- who were then a couple -- were later found and taken into custody at their home.
Rios and Contreras further admitted in their plea agreements to committing armed robberies against two victims outside a bar in the Florence-Firestone area earlier the same day.
The defendants each could have faced up to life in prison, but prosecutors agreed to seek terms of between 35 and 50 years in prison for Rios and Cisneros, and the term of 35 years for Contreras.
"Gangs bring death and destruction, most often upon the very communities they claim to represent," U.S. Attorney Martin Estrada said Friday.
"These defendants coldly and callously murdered an innocent man who grew up in our community and returned home to give back to the city he loved. I hope the major sentences we announce today bring some degree of solace to Officer Arroyos' family, friends, and colleagues."
Villanueva indicated at the time of the arrests that he directed detectives to take the case to federal prosecutors because of his opposition to District Attorney George Gascón's decision to no longer pursue sentencing enhancements in gang cases.
Those enhancements in a state murder case can mean the difference between a life term with the possibility of parole and never being released from prison.
Anderson said after sentencing the three defendants that when the gang members decided to rob Arroyos, "they literally threw their lives away."
City News Service contributed to this report.