Another witness, a truck driver who was at a nearby Burger King, told the attorneys that he and two other witnesses, a woman and her friend who both saw the shooting, were put in police cars, taken to a station and interviewed for hours in separate rooms.
"He kept describing it and he said the police were visibly angry with him and arguing with him about what happened, saying, 'That's not what happened,' " Robbins said. "He'd say, 'Well, that's what I saw.' They said, 'No, you're wrong.' "
Mayor Rahm Emanuel:The video tape was suppressed, witnesses were intimidated, reports fabricated, and an indictment was delayed for over a year — all in an effort to safeguard his reelection.
At least three witnesses to the Laquan McDonald police killing were questioned for hours, threatened by officers and ordered to change their accounts to match the official Chicago police version of the shooting, the attorneys for the teen's estate say.
The allegations are contained in more than 3,000 pages of recently released documents related to the case. The attorneys also allege that police officers up the chain of command fabricated witness accounts to support the way officers at the scene described the October 20, 2014, shooting as justified.
"It's not just the officers on the street," attorney Jeffrey Neslund told CNN. "It's a lieutenant, a sergeant and detectives -- and the lengths they went to justify what simply was not true."
The woman, Neslund alleged, was so appalled when shots rang out that she yelled at Van Dyke: "Stop shooting.""There's a reason they kept us there 'til 4 a.m.," the woman told McDonald's family, according to Neslund. "One officer said he was going to get me."When the witnesses refused to change their statements, Robbins wrote, "the investigating officers simply fabricated civilian accounts in the reports."
CNN contacted Neslund and Michael Robbins after the city released the documents to the news media in response to multiple Freedom of Information Act requests.
Asked if they stood by the accusations they made in letters to the city's corporation counsel last March, Robbins said, "Absolutely."
"You have a false narrative put out by police," he said, "outright lies to cover up an illegal shooting, corroborated by other officers."
CNN asked the Chicago Police Department for a reaction to the allegations. "This is the first time I'm hearing of that allegation," spokesman Anthony Guglielmi said. "But this is why we want an independent investigation to look at every fact. But unfortunately, we're not able to comment on any specific incident."
CNN legal analyst Joey Jackson said the allegations made by Neslund and Robbins are a significant development.
"In the event that it's true, you have multiple underlying charges: intimidating witnesses, falsifying public records and you have a conspiracy that more than one person was involved," Jackson said. "This has the potential of taking down a lot of people in that police department."