Video of a violent assault posted to Instagram led to the arrest of four San Bernardino County men, officials announced Friday.
An anonymous source last week sent deputies the social media video that showed several people attacking a 40-year-old man at Los Amigos Park in Rancho Cucamonga, the San Bernardino County Sheriff's Department said in a news release.
The video shows a man, later identified as 18-year-old Michael Alejo, punching the victim in the face and immediately knocking him unconscious, according to the agency.
The second suspect, 22-years-old Aaron Kulinski, then runs up to the victim who was on the ground and kicks him in the head, before he and Alejo continue beating the victim as a third suspect, 19-year-old Shant Whitfield, "encouraged the beating and instructed the others to check the victim’s pockets," the Sheriff's Department said.
Officials said Kulinski then stole a pocket knife from the victim after going through his pockets.
The victim got to his feet and tried to get away, but a fourth suspect, identified as 20-year-old Elijah Barragan, ran up to him and punched him in the head, again rendering him unconscious, officials said.
"The beating continued by all four suspects as the video ended," the Sheriff's Department said.
The day after receiving the violent video, detectives from the Rancho Cucamonga Station contacted Kulinski and Whitfield took them both into custody.
About five days later, Alejo was found and arrested near his home in Ontario.
Officials said detectives found "gang paraphernalia" at the homes of Kulinski, Alejo and Whitfield.
Barragan turned himself in to the Rancho Cucamonga Station on Tuesday.
Alejo and Whitfield were released on $100,000 bail, while Kulinski and Barragan remained in custody Friday on $150,000 and $50,000 bail, respectively.
It's still unclear what motivated the attack, officials said. The case remains under investigation and no further details were available.
Anyone with information is urged to contact the Rancho Cucamonga Sheriff’s Station. Callers wishing to remain anonymous can call the We-tip Hotline at 1-800-78-27463.