UPDATE: Cook County State's Attorney Anita Alvarez addressed questions surrounding the missing footage at a press conference Tuesday. Click here for more.

Chicago police officers deleted footage from a security camera at a Burger King restaurant located fewer than 100 yards from where 17-year old Laquan McDonald was shot and killed, according to a Chicago-area district manager for the food chain.

McDonald was shot 16 times by a Chicago police officer on the night of October 20, 2014. Nine of the shots struck McDonald in the back, according to the Medical Examiners report.

The 86-minutes of missing video runs from 9:13 p.m. to 10:39 p.m., according to the lawyers for McDonald’s family. He was shot at approximately 9:50 p.m.

The Burger King sits at 40th and Pulaski and has a series of outside security cameras. On the night of the shooting, McDonald was trailed by Chicago police officers through the Burger King parking lot after a call about a man with a knife, according to attorneys for the McDonald family.

Just south of the restaurant, McDonald was shot after police on the scene said he posed a "very serious threat" to the officer’s safety. But that claim is disputed by attorneys for McDonald’s family and by some eyewitnesses that night.

"One witness, this witness told us this was an execution. That’s his word," said attorney Jeff Neslund, who along with Michael Robbins, represents McDonald’s family.

After the shooting, according to Jay Darshane, the District Manager for Burger King, four to five police officers wearing blue and white shirts entered the restaurant and asked to view the video and were given the password to the equipment. Three hours later they left, he said.

The next day, when an investigator from the Independent Police Review Authority asked to view the security footage, it was discovered that the 86 minutes of video was missing.

In a statement, a spokesman for the IPRA said: "We have no credible evidence at this time that would cause us to believe CPD purged or erased any surveillance video."

But according to Darshane, both the cameras and video recorder were all on and working properly the night of the shooting. So what happened? One of the detectives, he believes, deleted the files.

"We had no idea they were going to sit there and delete files," Darshane said. "I mean we were just trying to help the police officers."

The missing video, all sides agree, would not have shown the actual shooting but attorney’s for McDonald’s family contend it could have shown events leading up to the shooting.

"Our first time down at the Burger King restaurant when we started talking to employees, watching the Burger King video, when we realized video had been deleted, or is missing, absolutely we knew something was up," said Jeff Neslund.

While the video from the Burger King is missing, the shooting of McDonald was captured on a police dashboard camera. That video has not been made public.

The FBI, the U.S. Attorney and the Cook County State’s Attorney’s office are all investigating the McDonald shooting.

As is the Independent Police Review Authority.

"I don’t regard them as independent and I don’t regard them as investigators," said attorney Candace Gorman. She represents the family of Divonte Young who was shot and killed by a Chicago Police officer in August 2012. The officer said he was in fear of his life after Young shot at him.

IPRA in calling the shooting justified noted, "No weapon was found on or near the Subject so it was surmised that a civilian had removed the gun."

In a civil rights case filed in federal court, Gorman contends IPRA investigations are a whitewash.

"Their policy is to exonerate any officer that’s involved in a shooting and the officers all know it," she said. "They have complete impunity, and they know they will never be called on the carpet by the city of Chicago or the so-called independent investigative unit."

IPRA responded saying its investigations are done "fairly, objectively and thoroughly. IPRA’s policy is to reach the proper conclusion relative to the officer’s use of deadly force based solely on the evidence." And that, "Ms. Gorman could not be more wrong."

City Inspector General Joe Ferguson's office is, according to the IG's website, auditing the "accuracy and completeness of IPRA’s reporting on officer-involved weapons discharges and investigations."

A spokeswoman for the IG’s office says the audit is ongoing.

After repeated requests, the Chicago Police Department did not comment.