The report added that the fired officers "grieved their discharge and arbitration dates have yet to be scheduled".
The security officer who first pulled Dr. David Dao from his seat has been fired. The flight crew then called Chicago Department of Aviation officers, who were captured on video forcibly removing Dao from his seat and dragging the bloodied passenger down the aisle by his wrists.
"The investigation further established that the sergeant deliberately removed material facts from the third" officer's "To/From Report" and approved reports without all essential information", the inspector general said. In addition to firing the two officers, the department issued five-day suspensions to two others, according to the report.
The city of Chicago conducted an internal investigation on police behavior at the origin of this incident, and announced that two of the four officers involved had been dismissed while the other two had been suspended for five days.
Chicago's Office of Inspector General concluded in a report released Tuesday that three aviation security officers and one aviation security sergeant "mishandled" the situation, the newspaper noted.
The incident left Dao with injuries that his attorneys describe as a broken nose, two chipped teeth and a sinus problem that will require surgery.
In the event of an overfull flight, an airline may entice passengers with compensation to voluntarily give up seats, and, if there are not enough volunteers, may "bump" passengers.
One of the suspended officers chose to resign.
But viral video of the incident fast became an worldwide symbol of passenger discontent with the flying experience and a civic embarrassment that damaged Chicago's reputation as an global tourist destination.
He was later filmed standing up, saying over and over "just kill me".
Demetrio said in a statement that Dao "is neither vindictive nor happy" about the inspector general's findings. The amount that can be offered to passengers to give up their seats was also increased.