Another instance of police brutality has gone viral, and the incident has sparked an investigation.

In a video posted on Facebook, Sean Williams can be seen sitting on a curb in Lancaster, Pennsylvania. A police officer tells him, “Legs straight out, or you’re getting tased.”

Williams straightens his legs, and when instructed to cross them, he attempts to follow the order. Suddenly, an officer tases him.

“You’re really gonna tase him? He was sitting down,” witness Juan Almestica, who recorded the incident, said when speaking to WGAL.

The officer then made Williams lie on his stomach. He complied and was taken into custody.

Almestica believes the officers’ instructions confused Williams.

“He first put them straight, and then he said cross your legs, so he tried to cross his legs, [and the officer] tased him in the back,” Almestica said.

Williams was booked on a prior warrant for public drunkenness and possession of a controlled substance, The Hill reports. He was later released on bail.

The officers arrested Williams after receiving a call about a man with a bat threatening people in the area. Williams did not have a bat on him, and no bat was found in the area near the site of his arrest.

The Lancaster Police Department released a statement defending the use of force.

“This is done as a measure of control to [ensure] that if someone is going to flee or offer physical resistance, they will have to move their legs under them to do so,” a spokesperson wrote. “Non-compliance is often a precursor to someone that is preparing to flee or fight with Officers.”

Lancaster Mayor Danene Sorace posted a video expressing her disappointment in the officers’ actions and said the incident is under investigation. She also said she is pushing for a body camera program.

“Like you, when I saw the video I was upset by it, and it is a great concern to me. We take the use of force very seriously,” said Sorace.

“We are currently awaiting word related to some federal grant funds from the Department of Justice related to funding and look forward to continuing to keep the public abreast of those developments as well as the outcome of this investigation,” she said.