United Airlines Passenger Allegedly Rapes Woman During Flight.

The woman said the 40-year-old man attacked her while others slept on the flight from Newark, New Jersey, to London's Heathrow Airport, British newspaper The Sun reported.

She complained to cabin staff who called ahead to inform the police, the tabloid said.

When contacted by Newsweek, London's Metropolitan Police said in a statement that officers at the London airport were alerted at 6:39 a.m. on Monday, January 31, "to an incident on an inbound flight."

"Officers met the aircraft on arrival and arrested a 40-year-old man on suspicion of rape," the statement said, adding that the man had been released under investigation.

"The complainant, a woman, is being supported by specialist officers and enquiries are ongoing," police said in the statement.

A source told the paper that the pair had been in separate rows in business class. When police arrived on board, they "carried out a thorough examination of the area of the plane where it was said to have happened."

"She was distraught and reported it to cabin staff who radioed ahead to police, who were waiting as the plane came into land," the source said.

A spokesperson for United Airlines told Newsweek: "Our crew called ahead and notified the local authorities as soon as they became aware of these allegations. We will cooperate with law enforcement on any investigation."

In April 2018, the Federal Bureau of Investigation (FBI) said there had been an increase in the number of reported sexual assaults on commercial flights and urged flight passengers to be aware of their surroundings.

The FBI said it had opened 63 investigations into sexual assault on aircrafts in 2017—compared with 38 in 2014.

CNN reported in 2017 the exact number of assaults on commercial flights in the U.S. is difficult to know because there is no federal regulatory agency that tracks nationwide data, so the number of assaults was probably much higher.

Brian Nadeau, assistant special agent in charge with the Baltimore division of the FBI, said that it was important that passengers notified authorities about sexual assaults immediately. This would allow the FBI "to do the investigation, collect witnesses, get the flight crew for statements prior to everyone departing for their next destination."

David Rodski, an FBI special agent assigned to investigate crimes out of Baltimore-Washington International Marshall Airport, told The Washington Post in 2018 that sexual assaults, which typically occur on long overnight flights, are "increasing every year...at an alarming rate."

While "statistically still very rare," Rodski said that "it is very good ­advice for people traveling to have situational awareness."