OAKLAND (CBS SF) — The Oakland Police Department is investigating one of its officers after a video posted to Facebook over the weekend shows him spitting at the person recording him.

The person who uploaded the video said in the caption the unidentified officer spat on his friend who was the one recording the video on Friday.

The video shows police officers appearing to question a group of people standing outside a car at a gas station.

When the camera swings over to the police officer, he appears to take something out of his mouth and throw it at the person recording, just before he spits at him.

Spitting on a person could be considered battery under California Penal Code 242.

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Two of the young men in the video said they stopped at the gas station Friday night to grab something to drink, not knowing there was a sideshow happening nearby, when they were questioned by a police officer.

In an interview with KPIX-TV, the men said they only wanted to be identified by their first names, “Josh” and “Johnny.”

They said the officer who approached them wanted to know about their cars. “He started harrassing us giving us issues about my car, saying it was modified and basically just kind of giving us trouble,” Josh said.

Johnny said one of their friends called the officers “pigs.” After that, the officer called back-up, and Josh and Johnny said they were quickly surrounded by officers, including one who was chewing sunflower seeds.

“He tried to throw a chewing seed at me and he missed and he spat one at me on my left side of the shoulder,” Johnny said. “I was really surprised cause I felt like that was assault.”

Moments later, the officer can be heard saying “if I had another, I’d do it again.”

Josh also said their vehicles were illegally searched. “We didn’t say they could enter our vehicles,” he said. “There was no reason for them to enter our vehicles at any point … I just kept telling him, ‘I didn’t allow you to search the car,’ or ‘I don’t feel comfortable with you doing that.'”

“The Oakland Police Department immediately initiated an Internal Affairs Investigation when we were made aware of this incident,” said spokeswoman Officer Johnna Watson Monday. “We pride ourselves on professionalism, respect for others, relationships and community trust building. We take this matter seriously and will conduct a thorough investigation.”

Carlos E. Castañeda is Senior Editor, News & Social Media for CBS San Francisco and a San Francisco native. You can follow him on Twitter or send him an email.