The contretemps on Monday unfolded as JetBlue Flight 1052, a regional Embraer 190 jet, landed at Kennedy around noon — on time — with 100 passengers aboard and pulled up to the gate, said another law enforcement official, who spoke on the condition of anonymity because the investigation was continuing.

The official offered the following account:

One passenger stood up to retrieve belongings from the overhead compartment before the crew had given permission. Mr. Slater instructed the person to remain seated. The passenger defied him. Mr. Slater reached the passenger just as the person was pulling down the luggage, which struck Mr. Slater in the head.

Mr. Slater asked for an apology. The passenger instead cursed at him. Mr. Slater got on the plane’s public-address system and cursed out the passenger for all to hear. Then, after declaring that 20 years in the airline industry was enough, he blurted out, “It’s been great!” He activated the inflatable evacuation slide at a service exit and left the world of flight attending behind.

In short order, his brick two-story house on Beach 128th Street in the Rockaways, just off the ocean, was swarmed by detectives and uniformed officers from New York City and the Port Authority. “It was like there was a hostage in there,” said Curt Krakowski, who was working on the deck of a house across the street.

Mr. Slater, Mr. Krakowski said, “had a smile on his face when the cops brought him out, like, ‘Yeah, big deal.’ ” Mr. Slater was taken to a Port Authority police building at the airport and was expected to be held overnight.

One person familiar with the investigation said JetBlue took more than 20 minutes to notify the Port Authority police, allowing Mr. Slater time to get home. A spokesman for the airline declined to comment when asked about the delay, and a Port Authority spokesman said, “In matters of criminality, the Port Authority Police Department should be notified immediately.”