A deputy U.S. marshal traveling to London to help extradite a criminal defendant has been taken into custody by British authorities after he was accused of sexually abusing a female passenger on a Delta Airlines flight, four law enforcement officials said.

The federal marshal was one of two deputies traveling on a Delta flight from New York City’s John F. Kennedy International Airport to London when the woman complained to the flight crew that she had been inappropriately touched during the flight, the sources said.

A Delta spokesman confirmed there was an incident on the flight.

“Due to unruly passenger behavior while in flight, Delta Flight 1, JFK to London-Heathrow, was met by local law enforcement upon landing, and Delta is cooperating with their investigation,” the spokesperson said.

Two law enforcement sources said the two federal marshals had been drinking during the flight. The second marshal was being sent back to New York on Wednesday night without facing any charges.

Both deputies, who are assigned to the Eastern District of New York, were en route to London to bring back a suspect wanted in Brooklyn on federal fraud-related charges.

Metropolitan Police in London said in a statement that their officers at Heathrow Airport were informed that the marshal had “sexually assaulted other passengers and crew” aboard the flight, adding that the marshal, who is 39, was arrested on suspicion of sexual assault and remains in custody.

A spokesman for the U.S. Marshals Service said it was aware that the officer “engaged in serious alleged misconduct while intoxicated on an inbound flight.” The spokesperson added that the Marshals Service is cooperating with U.K. law enforcement and other agencies.

“The U.S. Marshals Service takes seriously any allegations of misconduct by its employees. The alleged actions of the employees do not reflect the professionalism of the thousands of employees of the USMS or its core values,” the statement read.

Jonathan Dienst

Jonathan Dienst is chief justice contributor for NBC News and chief investigative reporter for WNBC-TV in New York.

Jay Blackman

Jay Blackman is an NBC News producer covering such areas as transportation, space, medical and consumer issues.

A deputy U.S. marshal traveling to London to help extradite a criminal defendant has been taken into custody by British authorities after he was accused of sexually abusing a female passenger on a Delta Airlines flight, four law enforcement officials said.

The federal marshal was one of two deputies traveling on a Delta flight from New York City’s John F. Kennedy International Airport to London when the woman complained to the flight crew that she had been inappropriately touched during the flight, the sources said.

A Delta spokesman confirmed there was an incident on the flight.

“Due to unruly passenger behavior while in flight, Delta Flight 1, JFK to London-Heathrow, was met by local law enforcement upon landing, and Delta is cooperating with their investigation,” the spokesperson said.

Two law enforcement sources said the two federal marshals had been drinking during the flight. The second marshal was being sent back to New York on Wednesday night without facing any charges.

Both deputies, who are assigned to the Eastern District of New York, were en route to London to bring back a suspect wanted in Brooklyn on federal fraud-related charges.

Metropolitan Police in London said in a statement that their officers at Heathrow Airport were informed that the marshal had “sexually assaulted other passengers and crew” aboard the flight, adding that the marshal, who is 39, was arrested on suspicion of sexual assault and remains in custody.

A spokesman for the U.S. Marshals Service said it was aware that the officer “engaged in serious alleged misconduct while intoxicated on an inbound flight.” The spokesperson added that the Marshals Service is cooperating with U.K. law enforcement and other agencies.

“The U.S. Marshals Service takes seriously any allegations of misconduct by its employees. The alleged actions of the employees do not reflect the professionalism of the thousands of employees of the USMS or its core values,” the statement read.

Jonathan Dienst

Jonathan Dienst is chief justice contributor for NBC News and chief investigative reporter for WNBC-TV in New York.

Jay Blackman

Jay Blackman is an NBC News producer covering such areas as transportation, space, medical and consumer issues.