A Delta Airlines pilot was arrested by federal agents just moments after landing a flight in San Francisco, leaving passengers and crew stunned.

The pilot, whose name has not been released, was taken into custody shortly after the plane arrived from Minneapolis around 9:30 p.m. Saturday, according to the New York Post.

Passengers were preparing to get off the plane when about 10 federal agents — including members of Homeland Security Investigations (HSI) — suddenly boarded. Witnesses said the agents rushed toward the cockpit. One passenger, Sarah Christianson, told the San Francisco Chronicle that the other pilot came on the intercom, saying he had “no idea what just happened.”

The sh0cking a**est was reportedly linked to an investigation involving child sexual abuse material, according to law enforcement sources who spoke with Fox Business.

Christianson said the agents escorted the pilot off the plane and down the jet bridge in full view of those onboard.

“A group of people with badges, g*ns, and different agency vests/markings were pushing their way up through the aisle to the cockpit,” the passenger reported to the San Francisco Chronicle.

After the pilot was led off the plane by federal agents, passengers said another group of officers returned shortly after to collect his bags.

A passenger named Sarah told ABC7 News that the incident was “traumatic to watch,” noting that some of the officers seemed to be wearing Homeland Security badges. According to the San Francisco Chronicle, other agents involved were believed to be air marshals.

“They barged through and stormed the cockpit,” Sarah told ABC7 per PEOPLE. “They removed the copilot, cuffed him, presumably arrested him, and brought him back down the aisle to deplane.”

She said the rest of the passengers were “shocked and stunned” by what happened.

Calling the situation “just a huge question mark,” she said many were left demanding answers.

She said she wasn’t sure if the pilot was being taken away for committing a crime or something else entirely, and the uncertainty left her deeply unsettled. After her husband picked her up at the gate, she got into the car and broke down in tears.

The a**est was carried out by Homeland Security Investigations (HSI), a division of Immigration and Customs Enforcement (ICE). HSI is known for handling immigration raids and criminal investigations. However, it’s unclear if this arrest had anything to do with the pilot’s immigration status per the New York Post.

An HSI spokesperson confirmed that their agents assisted the Contra Costa County Sheriff’s Office in executing an arrest warrant.