A statement from the airline read that the captain of flight 4519 decided to land at Corpus Christi International Airport after the crew became concerned about the behavior of one of the passengers.
Henrietta Mokwuah said she witnessed a woman try to open an emergency exit while they flew thousands of feet in the air.
"Oh yeah, she tore off a piece of it. There was the frame, that was on the door. She ended up breaking it off," said Mokwuah. "We've been visiting Corpus Christi over that for four to five hours."
Mokwuah said the woman appeared unstable. She said the woman was pacing up and down the aisle of the plane.
"It's been pretty trying. You're not just going to do that kind of stuff in America anymore," said Mokwuah. "I don't think anybody thought she was going to get to the door. It was pretty stressful for hours."
Terrance Franklin said he saw the same woman in the terminal at Los Angeles International Airport. The flight was headed for Houston's Hobby Airport.
It diverted to Corpus Christi International Airport following the incident.
"Prior to the flight, she had a couple of outbursts saying she was being treated wrong. Some things with the government -- personal and political," said Franklin. "Once we got in the air, that's when it all started again. She was walking back and forth. I knew something wasn't right."
Itza Sanchez was also on the Southwest Airlines flight. She said an off-duty police officer, along with another man, helped take down the disruptive passenger.
Cleveland ISD Police Chief Rex Evans identified the officer as Pamela Minchew. He said she's been with the department just two weeks.
Minchew was on vacation with her family in California and was headed home to southeast Texas.
"She was definitely a hero for us," said Sanchez. "I am exhausted and ready to get home. It's been a long day."
Corpus Christi Airport Police told Eyewitness News the FBI is investigating the situation.
The passenger was questioned by authorities and has not been formally charged with a crime.
KTRK-TV reached out to Officer Minchew for comment but was unable to make contact.