Story highlights Officials have terminated an officer and a sergeant involved in the forcible removal of a United passenger, officials say

Employees made "misleading statements and deliberately removed material facts from their reports," investigation finds

(CNN) Chicago aviation officials fired two officers and suspended two others involved in the forcible removal of a United Airlines passenger from a packed flight.

Cellphone footage showed security officers on April 9 dragging Dr. David Dao by his arms and legs down the aisle and off the Louisville, Kentucky-bound flight before it took off at Chicago O'Hare International Airport.

Dao was left bloodied and bruised in the incident that created a firestorm for the airline.

Three Chicago Department of Aviation security officers and a sergeant "mishandled a nonthreatening situation that resulted in a physically violent forcible removal of a passenger" aboard the flight, a City of Chicago Office of Inspector General investigation found, officials said Tuesday.

Employees made "misleading statements and deliberately removed material facts from their reports," the investigation found.