Discuss as:

Man arrested in connection of rape on bus, L.A. police say

A man has been arrested in connection with the rape on a public bus of a mentally disabled 18-year-old woman, sheriff's officials said on Friday.

The woman, who officials said has the mental capacity of a 10-year-old, told police she was raped about 5 p.m. Wednesday after she boarded Bus Line 217 at La Cienega and Jefferson boulevards in Culver City, Calif., according to the Los Angeles County Sheriff’s Department.

Sheriff's officials are expected to announce details about the arrest at a 2:30 p.m. (5:30 p.m. ET) press conference.

The man who was seen through surveillance video getting off the bus, apparently boarded the bus the same time as the woman.

He followed her to the rear of the bus, then sat down, officials said. Then, without warning or provocation, the man stood and faced her while positioning himself between her legs when he sexually assaulted her, sheriff's officials said.

After 10 minutes, the man, pictured here on bus surveillance camera, stopped his alleged assault and got off the bus at Sepulveda Boulevard and Slauson Avenue, the route’s last stop.

"She did not scream or shout out. She was too afraid to do so," said Sgt. Dan Scott with LA County Sheriff's Department.

According to investigators, the bus driver was unaware of the alleged assault happening in the back of the bus and by the time the only other passenger on the bus attempted to alert the driver, the alleged attacker was already getting off the bus.

He was described as black, between 18 and 20-years-old. He's between 5-foot-8 and 5-foot-10, weighs between 150 and 160 pounds and has short, cropped hair.

At the time of the incident, he was wearing jeans and a hooded sweatshirt with narrow horizontal stripes, police said.

"We believe, based on the proximity of the crime being in such a public place and in broad daylight, that there's a high likelihood he may have done this before," Scott said.

More content from NBCNews.com:

Follow US news from NBCNews.com on Twitter and Facebook