The family of a black Illinois teen seen being pinned down by a white off-duty police officer in cell phone footage wants answers. Footage shared on social media shows 15-year-old Jordan Brunson being held down and threatened by an off-duty Lansing Police Department officer, CBS Chicago reported Monday. In the video, the unidentified off-duty officer repeatedly mentions trespassing and, at one point, threatens the teen's life.

"So this is what happens when you walk on someone's grass," Facebook user Ann Falls wrote when sharing footage of the incident, which occurred Saturday. "My little cousin is damn near killed. This guy is a LANSING POLICE OFFICER and our family can't get anywhere filing a report on him. I reed FB to share and share this needs to go VIRAL!! I'm sick of walking while black being a problem! As you can hear his friend videoing is not black but he's not being harassed!!"

In the video, the officer can be heard telling the teen that if he comes onto his "fuckin' property" that he could "fuckin' kill ya."

In an interview with WGN-TV Monday night, Brunson said he was trying to help his friend—the one who later filmed the incident above—after he had been "beaten up pretty bad" in an unrelated fight Saturday afternoon. "I was examining him," Brunson said. The officer, according to Brunson, then appeared out of nowhere and grabbed them both.

Brunson said the officer never told them to get off the property or identified himself as a police officer. "I was scared, but I was trying to keep calm at the same time," he said.

In a press release Sunday, Lansing police said the incident was under investigation. "The Lansing Police Department is aware of the video that has been subsequently posted on social media regarding the incident, and had initiated an investigation into the matter prior to its public posting," the statement said. Read the statement in full below.

The Lansing Police Department did not immediately respond to Complex's request for comment.