sw airlines passenger choked
A Southwest Airlines flight from Los Angeles to San Francisco on Sunday night was forced to turn around and make an emergency landing after a passenger allegedly choked the woman in front of him for reclining her seat.

The FBI is investigating, although no arrests were made early Monday morning.

"An individual was detained for questioning following the return of a Southwest aircraft to LAX based on allegations of an assault involving a fellow passenger," according to FBI spokeswoman Laura Eimillier. "No arrest has been made at this time and the investigation is continuing."

Southwest Airlines also confirmed to NBC News that the pilot made an emergency landing because of a "rapidly escalating situation" between two passengers. A spokeswoman said that 136 customers - all but the man involved - were switched to another flight and eventually made it to San Francisco International Airport by 1:48 a.m. Monday.

And audio transmission of the pilot talking, obtained by NBC News, also confirms some type of event on board: "Evidently, we've got two passengers who are in a physical altercation, so we need to get turned around back to LAX," the pilot is heard saying.

And a passenger on board took a short video of the aftermath, and shared it with NBC Bay Area.

The 15-second clip shows a flight attendant and a man with a badge standing near the cockpit and talking to a woman wearing flip flops in the front row.

Their conversation goes like this:
Unknown male voice: You'll have to press charges.

Flight attendant, talking to unknown person: Yeah, you're going to regret that.

Woman in flip flops: What am I going to do? Am I going to stay here all night?

Man with badge: I need you to sign a private person's arrest. Because it didn't happen in front of me. It's a misdemeanor. So I can't do anything. We're going to take him off the plane.
Airport police officer Rob Pedregon said San Francisco-bound Flight 2010 left the gate around 10:25 p.m. Sunday. And a witness said the alleged choking took place soon after take-off.

A passenger who only identified herself as Melanie, and who posted a photo on Instagram, spoke with NBC News about what she saw. She was sitting one row ahead of the altercation.

Melanie said she saw a woman push her seat back to recline and then the man who was sitting behind her "started choking her. She shouted for help and the crew came to see what happened. The man stayed very calm during the whole situation."

Melanie said the woman switched seats with a man sitting in the first row and the plane headed back to LAX. There, police cars met the plane, and the man was asked to leave the flight.

No additional details were given.