Investigators said the victim was befriended by the suspect, 29-year-old Herbert Daniel Ortiz, aka Herbert Ortiz Monroy, and the relationship lasted for several years.
"It started when (the victim) was 14," said L.A. County Sheriff's Lt. Carlos Marquez.
Ortiz was an assistant coach at Rosemead High School from 2007 to 2009. Since 2010, he has been a wrestling instructor for the Bad News Panthers Children Wrestling Club in Rosemead, which he founded.
The victim's mother notified authorities about the alleged abuse after she apparently saw a YouTube video that showed another boy saying that he had been victimized by Ortiz. The alleged victim in that video was warning viewers, specifically those living in Rosemead, to protect their children.
The mother recognized the suspect in the video as her son's assistant wrestling coach. She spoke to her son and he told her that he had been victimized by the suspect. Officials did not release any more details, but they said the alleged crimes happened in the cities of Rosemead, El Monte and Baldwin Park.
Authorities said they found out during their investigation that Ortiz was aware of the YouTube video. They believe he is intentionally eluding detectives. The suspect is 5 feet 8 inches tall and weighs about 160 pounds. His last known residence was in Baldwin Park.
Anyone with information was asked to contact Los Angeles Regional Crime Stoppers at (800) 222-TIPS.