Two of the three aviation officers who were responsible for violently dragging a doctor off a United flight were fired, while a third officer resigned over the incident.

A fourth officer, who was also involved was handed a five-day suspension, which was reduced to two after he appealed, NBC News reported.

The two who were fired held the rank of Officer and Aviation Security Seargent, according to Joseph Ferguson, Chicago's Inspector General. The disciplinary action is contained in Ferguson's quarterly report that was released on Tuesday.

The names of the officers were withheld, as is the norm when employees are fired, and were referred to according to their ranks.

Grounds for suspension and termination

According to Fergusson's report, the first officer violated the 'use of force policy' of the Department of Aviation, when he used excessive force in a non-threatening situation to drag the passenger off the plane.

This resulted in the passenger, Dr. David Dao, hitting his face on an armrest causing him injuries which included loss of teeth, a broken nose, and a concussion.

The second officer, on the other hand, was accused of making two conflicting statements which were found in two separate reports and were meant to mislead the investigation and throw it off-track.

The Seargent was also found guilty of omission and commission when he removed certain facts from the third officer's report and went on to approve it while it lacked all the essential information.

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The United incident

The incident happened aboard a United Airlines flight destined for Louisville from Chicago in April when Dao declined to give up his seat on the overbooked flight, for a crew member who was to work on a connecting route.

The security officers were then summoned by the airline staff and surrounded Dao's seat, and forcefully dragged him off the flight amid protests and dismay from fellow passengers.

A passenger managed to record the entire bloody episode using a cell phone camera, and the video went viral once it was posted on social media.

The incident proved to be a PR disaster for United Airlines and the management headed by Oscar Munoz, who is the CEO, were forced to offer a public apology and begin an investigation into the embarrassing incident.

Later in the same month, Dao and United Airlines announced they had reached an 'amicable' agreement over the incident.

A review of the Aviation Security Division's policies is currently underway and should be completed early next year.