A Chicago Burger King manager who accuses police of erasing surveillance video in the case of a black teenager shot last year by a white officer said Saturday he testified before a federal grand jury investigating the shooting.

Jay Darshane told the Chicago Tribune that the FBI also took the video recorder containing all of the fast food restaurant’s surveillance images.

The allegations of tampering has fueled the anger of protesters who say the city, police and local prosecutors have botched the case of Laquan McDonald’s death. After months of refusals, the city released police squad car footage of the shooting Tuesday in response to a judge’s order.

Both the police chief and the Cook County state attorney deny the Burger King video was altered.

The Burger King is yards from where McDonald, 17, fell when the first few rounds from Officer Jason Van Dyke struck him. It took minutes for police to demand the restaurant’s password-protected video, Darshane said.

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"I was just trying to help the police with their investigation," Darshane said. "I didn't know they were going to delete it."

He said that when the officers left, almost two hours later, there was an 86-minute gap in the recording, including the time surrounding the shooting.

Darshane told the newspaper he testified about the missing video before a grand jury earlier this year.

The Cook County state's attorney this past week announced a state-level charge of first-degree murder against the officer.

McDonald was shot 16 times after being pursued by police responding to a complaint about car break-ins. He was carrying a knife. The officer's attorney says his client fired because he feared for his life, and that he acted lawfully and within police department guidelines.

At a news conference announcing the charge, State's Attorney Anita Alvarez said forensic testing found no evidence that anyone intentionally erased the Burger King video. Police Superintendent Garry McCarthy called the allegation "absolutely untrue."

The Associated Press contributed to this report.

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