Kerry Trotter, 20, was arrested at 6:30 a.m. Friday, according to the Los Angeles County Sheriff's Inmate Information. He is being held on $1 million bail.
The sexual assault happened at 5 p.m. Wednesday at the Metro Bus stop on La Cienega and Jefferson boulevards. Sheriff's detectives say the victim boarded the No. 217 bus and a male passenger followed her to the back.
"She sat down, he sat down near her, got up almost immediately and proceeded to attack her," said Los Angeles County Sheriff's Det. Dan Scott.
Investigators say cameras on-board the bus captured the suspect raping the woman as she suffered in silence during a 10-minute trip to Slauson Avenue and Sepulveda Boulevard. The woman is said to have the mental capacity of 10-year-old.
"The victim did not scream, the victim told our detective that she was shocked, she didn't know what to do and she was in fear for her safety and for her life," said Scott.
According to the surveillance video, there were four other passengers on board. One seemed to try to get the attention of the driver, but the driver was unable to see what was happening. Investigators say there's no suspicion that the driver did anything wrong.
"This individual was blocking the view of the victim, and based on people that have analyzed this -- my detective -- she feels it's reasonable that there might have been suspicion but not enough to think there was a sexual assault," said Scott.
Trotter has a history of arrests for sexual assaults, but no convictions. It is not known yet whether there's any pattern of seeking out individuals who are disabled.
In this case, sheriff's suspect the assault was a crime of opportunity. They are still gathering information.
"We would urge anybody that is a victim of his or an attempted rape or anything of that nature, to please come forward.
Anyone with information about suspicious activity from Trotter is asked to call the Special Victims Unit at (562) 946-8282.
