While Dao continues to recover in a Chicago hospital, lawyers representing him filed a petition with an Illinois State court demanding the airline and the City of Chicago to preserve all surveillance videos, cockpit voice recordings, passenger and crew lists related to the flight, BBC reported.
'Because United has such a catastrophic PR problem, this case has a much greater value than such a case would normally have, ' he said.
The video of this bloody incident went viral on Internet and sparked social media uproar, in which many are echoing calls to boycott United Airlines.
Munoz, who had initially described Dao as "disruptive and belligerent", said Wednesday he felt "shame and embarrassment" and vowed such an incident would never happen again.
"To remove a booked, paid, seating passenger, we can't do that", he said.
On Monday, Munoz was roundly criticized for saying in a statement that he was sorry that the airline had to "re-accommodate these customers". Dao, a 69-year-old doctor, has also hired Thomas Demetrio, a high-powered personal injury lawyer, according to a statement from Demetrio.
Spokeswoman Megan McCarthy said Wednesday that the passengers can take the compensation in cash, travel credits or miles.More news: Trump's 'truly great' pick for Supreme Court sworn in
Munoz on Tuesday promised a thorough review of United's policies for handling situations where it has sold more tickets than seats available, including how it offers incentives to customers to take a later flight, and how United works with airport authorities and local law enforcement.
His legal team planned to hold a news conference Thursday to discuss the matter with reporters.
The request was filed a few hours before the Chicago Department of Aviation said it had placed two more officers on administrative leave until further notice as a result of the incident. The video showing Dao, who is now hospitalized after the incident, being pulled out of his seat and screaming as officers dragged him down the aircraft at Chicago O'Hare airport, received millions of views.
Chicago Aviation Commissioner Ginger Evans will also speak.
US Representative Jan Schakowsky said she plans to introduce legislation that would bar airlines from involuntarily bumping passengers from overbooked flights and require airlines to seek volunteers to switch to later flights before boarding.
A spokesperson said all those on Flight 3411 on Sunday night from Chicago to Kentucky would be "receiving compensation for the cost of their tickets", according to reports from U.S. media.
In an effort to calm the backlash, United also announced that passengers on United Express Flight 3411 would be compensated equal to the cost of their tickets.