They said they want to make sure the city and the airline preserve surveillance video showing passengers boarding Sunday's Flight 3411 to Louisville at O'Hare International Airport.
Lawyers for the passenger, identified as Dr. David Dao, have filed papers with the IL state court requesting that United Airlines and the City of Chicago, which operates the airport, preserve all documents and evidence related to flight 3411, including cockpit voice recordings, passenger manifests, crew lists, video recordings and any other materials related to the flight, in which their client was forcibly removed by airport law enforcement officials and injured while being dragged down the aisle.
That eventually led to the video everybody has seen - a 69-year-old man being dragged off the plane by security officers after refusing to give up his seat. "We are also reaching out to the passenger to talk directly to him and further address and resolve this situation".
In an interview with ABC's "Good Morning America" aired Wednesday, the chief executive of United Airlines said the carrier will no longer ask police to remove passengers from full flights.
Dr Dao was pulled off Sunday evening's flight because it was fully booked, and the airline wanted to get four passengers to leave to make room for staff members.
At first, the airline asked for volunteers, offering $400 and then when that did not work, $800 per passenger to relinquish a seat. All but Dao agreed to leave.
The CEO of the company, Oscar Munoz, said he was ashamed of the incident after he was the video where the man is seen being dragged by security officers down the aircraft aisle. He appears relatively passive while being dragged. "Kill me", and "I have to go home".
"That is not who are family at United is".
He was the only passenger removed from the plane, who was later permitted to board again.
US President Donald Trump has said what happened to Dao was "horrible". "But with all the bad press United is getting from this, do I think they would pursue anything? No". Dr. Dao's statement doesn't touch on what, if anything, the family of the victim may do going forward, but we'll keep you updated as news breaks.
Three officers involved in the incident have been placed on leave. Two more officers were suspended Wednesday. Officials have refused to say what procedures should have been followed.
Even if United could pursue legal action, Anthony Rickman, a former prosecutor turned defense attorney in Tampa, said the airline is already facing a public relations nightmare that would only be compounded by an attack on the passengers who captured the incident on video.