Los Angeles County Sheriff Alex Villanueva announced the arrests during a livestream of his weekly informational update. He did not disclose the suspects' names or additional details about the case.
The Sheriff's Department had previously said that three men and two women were detained in the Florence area of South L.A. on Tuesday as part of the investigation into the shooting of 27-year-old Officer Fernando Arroyos.
In an interview with ABC7 on Wednesday, Arroyos' mother described her son as someone who simply wanted to serve his community and help his family.
"I want to remember my son as a hero, for his work," Claudia Karin said tearfully in Spanish. "As a son, he was the best. As a grandson, he was the best. And, as I said, I wish all the best for my son."
Arroyos' stepfather, Jose Reyes, said he loved the fallen officer as if he were his own son.
"He was very educated, very good with me," Reyes said in Spanish. "We never had any arguments, were always in communication with one another."
Arroyos, a three-year veteran of LAPD assigned to Olympic Division, was shot near 87th and Beach streets Monday night. Investigators say a black pickup truck approached him and three suspects got out of the vehicle.
An apparent argument ensued before an exchange of gunfire, in which Arroyos was struck. Investigators say the off-duty officer was house-hunting with his girlfriend at the time of the incident.
Early Tuesday morning, a procession escorted Arroyos' body from the hospital to the coroner's office.
"We mourn the loss of one of our officers who was shot & killed in an armed robbery attempt. The officer was off-duty. We pray for the officer's family, and their fellow officers, during this time of pain and sorrow," the Los Angeles Police Protective League tweeted.
LAPD Lt. Rex Ingram remembered Arroyos as a "phenomenal young man, extremely bright, intelligent, humble, modest, and just a smile that would last for days."
An only child, Arroyos' coworkers say he had two dreams in life. His first was to be the first person in his family to go to college. He accomplished that by graduating from UC Berkeley with honors.
His second dream was to become an LAPD officer.
Eddie Martinez, a friend who grew up with Arroyos, said the slain policeman was "just a good kid, super straight-edge, always hard-working, really, in school."
Arroyos "definitely wanted the best for his family," Martinez said.