Hanford Police and the Kings County Sheriff's Office announced the arrest Thursday at a news conference.
The boy was arrested by Sheriff's deputies following a shooting that happened at 1 a.m. Thursday.
Deputies say that shooting happened on Jeff Road and Thomas Court on the Santa Rosa Rancheria.
When deputies arrived, they found a 19-year-old shooting victim who was quickly rushed to the hospital.
Investigators say the 16-year-old Hanford suspect, the injured shooting victim and a young girl were inside a car when they were asked about their gang affiliation by an unknown adult man.
That man has yet to be found by the Sheriff's Office.
The Hanford suspect and the girl were later stopped by a responding deputy in the parking lot of the Tachi Palace Casino Resort.
The deputy identified the boy as the suspect involved in Avalos' death and took him into custody. Deputies say the boy did not comply at first but eventually did.
Investigators say they found a loaded handgun that was later connected to the one used in the Hanford shooting.
RELATED: Man dies after being shot while driving in Hanford, police say
Avalos was shot in Hanford Wednesday afternoon on 10th Avenue near Lacey Boulevard.
Security camera video captured when Avalos' car rolled to a stop, and the suspect's black Nissan speeding away after the shooting.
Avalos was taken to the hospital and died less than an hour later.
The Hanford Police Department says they have not established any connection between Avalos and the 16-year-old boy.
Police say they do have the suspect's car in their possession.
Stay with ABC30 for the latest details on this developing story.