The security guard who was fired after apparently masturbating during a San Diego Chargers game on Sunday first touched himself prior to the game — and then tried again during halftime, according to a woman who caught the disturbing act on video.

The woman said she was sitting with her family in the front row of their section at Qualcomm Stadium when the unidentified security guard began masturbating during pre-game warmups. The guard clearly had his hand down his pants and was apparently masturbating, she told 10News.com.

The woman — whose identity was not revealed by the station at her request — said she saw the guard try to do it again around halftime, when she heard another horrified fan at the stadium yell: “Get your hands out of your pocket!”

The woman said she called the San Diego-based company Elite Security at least four times Monday to report what she witnessed.

“I said, ‘This is about the [Charger] girls,’” she told 10News.com. “’This is about what they’re doing,’ and [Elite] didn’t care.”

She explained the incident in a series of voice messages, but the person she was referred to didn’t get back to her until after she posted footage of the lewd act on social media.

The woman said she also contacted Chargers team officials, but was told that no one could immediately comment. She said she posted the video to protect the very people the security guard was hired to protect.

“This to me was very much like you don’t deserve this, you’re at work doing your job,” she said.

The woman said she didn’t mean to embarrass the security guard, but wanted to make sure his actions did not escalate at future NFL games or other events.

Lt. Scott Wahl of the San Diego Police Department confirmed the agency began investigating the incident on Tuesday.

“We are still investigating this situation,” Wahl wrote in an email Wednesday.

The man could face charges of committing a lewd act in public, a misdemeanor punishable by up to six months in jail or a $1,000 fine.

Elite Security fired the guard on Tuesday, less than 24 hours after several versions of the video surfaced online. A company spokeswoman said Elite would have no further comment on the matter.

“And we’re not going to be offering any additional interviews,” Kristen Roberts told The Post.

In a statement Tuesday, the company apologized to anyone who was offended by the “isolated” incident.

“Additionally, Elite has opened a formal investigation into the matter and has acted swiftly in terminating the employee involved,” the statement read.

The man did pass all state and federal background screening processes and completed all licensing requirements, the company said.

NFL officials, meanwhile, had no comment on the incident, referring all inquiries to the Chargers.

Bill Johnston, the team’s director of public relations, declined to comment. The team released a statement Tuesday confirming the “disturbing actions” of the guard.

“The Chargers, Elite Security as well as the San Diego Police Department are aware of the disturbing actions of an Elite Security staff member at Sunday’s game,” the statement read. “We apologize to any fans who may have witnessed the incident. Elite Security is currently investigating the incident and has vowed to take immediate and appropriate action.”