CHANTILLY, Va. – A United Airlines flight bound for China has returned to Washington Dulles International Airport for a child custody investigation.

The flight was bound for Beijing on Thursday afternoon, but law enforcement authorities asked that it return about five hours after takeoff. The FBI says it was alerted that a child on board was allegedly being taken out of the country illegally by his mother.

According to the FBI, the woman was taken into custody when the flight returned. The father took custody of the child.

The flight was allowed to take off again Thursday evening from Dulles airport.