Detectives with the Contra Costa Sheriff’s Office had been investigating Bhagwagar since April, the department said.

A pilot was arrested aboard a Delta Air Lines flight and federal agents took him into custody from the cockpit after the plane landed at San Francisco International Airport.

“A group of people with badges, guns, and different agency vests/markings were pushing their way up through the aisle to the cockpit,” a passenger, who had been seated in first class, told the outlet...