Federal agents arrested a Delta Air Lines co-pilot Saturday afternoon moments after his flight landed at San Francisco International Airport, in what authorities confirm is a case involving child sexual abuse material.

The flight had arrived from Minneapolis when multiple federal agents boarded the aircraft, reportedly pushing through first class and into the cockpit. According to eyewitnesses, passengers were instructed to remain seated while Homeland Security Investigations (HSI) officers entered the flight deck and removed the co-pilot in handcuffs.

Delta Air Lines has not publicly identified the crew member and referred all inquiries to law enforcement agencies. In a brief statement to media, the airline said it was cooperating with authorities.

Federal officials confirmed to multiple outlets that the arrest was made on the basis of a warrant issued out of Contra Costa County. Homeland Security stated the operation was conducted in support of the Contra Costa County Sheriff’s Office, though further details about the case, including the pilot’s identity, have not been released.

Fox News correspondent Bill Melugin, citing a senior federal source, reported that the arrest stems from charges related to child sexual abuse materials. The Department of Homeland Security later confirmed to the Associated Press that the pilot was detained under such charges.

It remains unclear whether the co-pilot is based in California, Minnesota, or another location, and KTVU reported it had not independently confirmed the suspect’s name or background as of Sunday evening.

The arrest is the latest in a series of recent high-profile incidents involving airline personnel, although such charges are considered extremely rare within the aviation industry. The Federal Aviation Administration (FAA) and Transportation Security Administration (TSA) have been notified, and further internal investigations are expected.

Delta has not yet disclosed whether the co-pilot has been suspended or terminated, pending legal proceedings.