A woman was raped onboard a train in Philadelphia while as many as 10 people stood by or possibly filmed the incident on their phones instead of dialling 911, police have said.
A 35-year-old homeless man is accused of sexually assaulting a woman shortly after 9pm on 13 October on a train run by Southeastern Pennsylvania Transportation Authority (SEPTA).
"As many as 10 people actually saw some part of the attack on this rider," SEPTA Transit Police Chief Thomas Nestel III told Philadelphia radio station WPHT.
"We were watching to see if somebody put a phone up to their ear indicating they might be calling 911. Instead, what we saw was people holding their phones up as if they were recording or taking pictures."
SEPTA spokesman John Golden said in a statement: "It may have been stopped sooner if a rider called 911."
CCTV footage from the train car showed the woman trying to fight off an attacker by repeatedly pushing him away as he initially groped her and then raped her, local media reported.
Up to 10 other passengers aimed their mobile phones at the attacker but no one intervened, police said.
One person, an off-duty SEPTA employee, finally called the police.
Transit police were quickly brought on board the train and stopped the assault before arresting the alleged rapist.
"He was on top of our victim and committing the assault when they entered the train," Mr Nestel said.
Fiston Ngoy is facing charges of rape, involuntary deviate sexual intercourse, sexual assault and other offences following the attack, local media reported.
He listed a homeless shelter in Philadelphia as his address and was held on $18,000 (£13,000) bail.
Local media reported he was scheduled for a court hearing on 25 October.
It has also been reported that the alleged attacker claims the encounter was consensual, but the woman denies that.
The attack allegedly took place after the woman took the wrong train at 9.15pm. Ngoy boarded minutes later before moving to the seat next to her.