People were seen running from multiple terminals at the airport after authorities said a possible noise that sounded like gunfire caused travelers to flee around 8:30 p.m.
Travelers at the airport tweeted that there were shots fired in different terminals and shared videos of people rushing out of the airport and onto the tarmac.
Airport police detained a person in a Zorro costume at one of the terminals, but he was later released.
The man in the Zorro costume said he was at the airport unaware of the panic that ensued inside the airport. He said he suddenly had police around him asking him to put his hands up and to get on the ground.
"They turned me over, put handcuffs on me and then told me what was going on...they searched me," he said. "What happened was somebody called and said there's a man in dark clothing out here. They got scared, I guess. But I'm sitting here calling for transportation. Next thing I know, they let me go. They explained to me that crazy stuff happens in the airports."
He said a few moments later the incident was over and that it was a misunderstanding.
The airport temporarily shut down the upper and lower levels for arrivals and departures of the central terminal area as part of the investigation. The short closure caused a massive traffic backup.
Breaking News Update: LA Airport Police have not found a shooter or proof of shots fired. Traffic is jammed at LAX. pic.twitter.com/46xzrmK0Tu— Melissa MacBride (@abc7melissa) August 29, 2016
A 30-minute ground stop was also issued on the south runway, which was requested because scared passengers self-evacuated onto the restricted tarmacs.
Several terminals were evacuated as a precaution, according to the airport's TSA. People were let back into the airport shortly before 10 p.m. and were told to call their airlines for updates on their flights.