Chicago's Aviation Department said on Wednesday that two more officers had been placed on leave in connection with the incident.
It's the incident that went viral and sparked worldwide outrage: a passenger who was literally dragged off a United Airlines flight.
A Chicago alderman says city-employed airport security officers "should not be doing the dirty work for the friendly skies airline". Four passengers, including Dr. Dao, were randomly selected for removal.
After three passengers agreed to relinquish their seats, Dao said he was a doctor and could not give up his seat because he had appointments the following day.
Demetrio said the family plans to file a lawsuit once the lawyer's investigators are completed and hinted that United Airlines may not be the only defendant in the case.
The airline initially communicated that the injured passenger was partially at fault for the situation and that he had become "disruptive and belligerent" when he was told to de-plane.
Video of the incident, which has gone viral on social media, shows three security officers from the Chicago Department of Aviation pulling the passenger out of his seat, and in the ensuing struggle, hitting his head on the armrest.
Munoz said in a note to employees Tuesday, April 11, 2017, that he continues to be disturbed by the incident Sunday night in Chicago, where a passenger was forcibly removed from a United Express flight.
"Seeing it on video made those emotions exacerbated", said Dao's daughter, Crystal Pepper. While I deeply regret this situation arose, I also emphatically stand behind all of you, and I want to commend you for continuing to go above and beyond to ensure we fly right.
NFL could fine players for arm wrestling at Las Vegas casino
Joe Lockhart , the NFL's executive vice president for communications and public affairs voiced his issues on the situation. What happens in Vegas (except in this case) stays in Vegas. "We don't see changing our current policies".
"There's really no word for it", said McCarthy, who attributed the confusion to the airline's own understanding of what unfolded on the flight as it gathered additional facts.
Demetrio said the family accepts "with gratitude" the airline's "staged" apology.
United CEO Oscar Munoz has publicly apologized and promised a review of the airline's procedures. Later, Munoz offered a more emphatic mea culpa, saying, "No one should ever be mistreated this way".
"He was a paying passenger, sitting on our seat in our aircraft and no one should be treated that way period", Munoz said.
Pepper said her father and mother had been traveling from California to Louisville, Kentucky, and had caught a connecting flight at O'Hare.
The City Council, concerned about the potential loss of tourism revenue, held a hearing with the Commissioner of Aviation Thursday.
DOT says if a passenger is bumped from their flight, they can be compensated.
Accounts from passengers have pointed to a pattern by United of forcing ticketholders from flights involuntarily, whether because a flight was overbooked or to make room for flight crew or VIPs.