Authorities in Philadelphia said several train commuters might have recorded the rape of a woman instead of intervening.
During a press conference on Monday, Southeastern Pennsylvania Transportation Authority Police Chief Thomas J. Nestel III, the Associated Press reported, said the victim was harassed for 40 minutes by the suspect, Fiston Ngoy.
Nestel said Ngoy harassed, groped, then raped the victim.
Police are looking into whether bystanders on the train recorded the assault.
"I can tell you that people were holding their phone up in the direction of this woman being attacked," Nestle told reporters, the news outlet reported.
Nestle added that authorities believe no one on the train called 911.
According to the AP, a transit employee who saw the attack was the one who called 911 because "something wasn't right" about the victim.
Superintendent Timothy Bernhardt told the AP that Ngoy was arrested by SEPTA police, who were waiting at the next stop.
The victim, who Bernhardt described as an “unbelievably strong woman” as she provided details about her attack and attacker, was taken to a nearby hospital.