A 35-year-old man in Pennsylvania is facing rape and assault charges after a woman was sexually assaulted on board a public transit train Wednesday night as riders witnessed the attack but did not intervene, authorities said on Friday.

The woman was assaulted at around 11 p.m. while riding the Southeastern Pennsylvania Transportation Authority (SEPTA) Market-Frankford line towards the town of Upper Darby.

“The assault was observed by a SEPTA employee, who called 911, enabling SEPTA officers to respond immediately and apprehend the suspect in the act,” Andrew Busch, a SEPTA spokesperson, said in a statement.

SEPTA officers arrested the man, later identified as 35-year-old Fiston Ngoy, according to Upper Darby Police Superintendent Timothy Bernhardt.

Surveillance video captured the entirety of the assault, giving investigators enough evidence to charge Ngoy with rape and assault, Bernhardt told NBC Philadelphia.

The video also shows how riders, who also witnessed the attack, did nothing to help the woman being assaulted, according to Bernhardt.

“It’s disturbing,” he said. “I’m shocked, I have no words for it. I just can’t imagine seeing what you were seeing through your own eyes and seeing what this woman was going through that no one would step in and help her.”

Investigators are also reviewing the videos in an effort to determine who was there and interview possible witnesses, Bernhardt added.

Bernhardt told NBC Philadelphia that he spoke to the woman on Friday and said she was doing okay after being taken to a hospital to be treated for her injuries following the assault.

Upper Darby police continues leading the investigation into the rape with assistance from SEPTA Transit Police. Investigators are also urging anyone who witnessed the attack to contact the authorities.

SEPTA is also urging possible witnesses to contact the authorities.

“The rape that occurred on SEPTA’s Market-Frankford Line Wednesday night (Oct. 13) was a horrendous criminal act,” Busch said. “There were other people on the train who witnessed this horrific act, and it may have been stopped sooner if a rider called 911.”

“SEPTA urges anyone who observes a crime being committed or any dangerous situation occurring to report it. Anyone witnessing an emergency should immediately call 911,” he added.

Ngoy remains in jail unable to post bail, NBC Philadelphia reported.