Two more officers involved in dragging a United Airlines passenger off a plane have been placed on administrative leave, according to a statement provided to Yahoo News.

“The Chicago Department of Aviation (CDA) continues reviewing the details surrounding the incident,” the CDA said in a statement released late Wednesday afternoon. “As part of our review, two additional officers have been placed on administrative leave until further notice. The employees’ collective bargaining agreement prohibits the CDA from releasing their names at this time.”

Initially, one officer was placed on leave Monday following the removal of 69-year-old Dr. David Dao from United Airlines Flight 3411, which was scheduled to fly from Chicago to Louisville, Ky., on Sunday. Dao was forcibly removed from the plane when he refused to give up his seat after being notified that United needed four volunteers to give up their seats to allow crew members to make the overbooked flight.

Dao was selected by the airline to give up his seat but refused, leading to the actions by the three officers. Videos of Dao being dragged through the aisle of the plane and then returning to the cabin with blood on his face went viral, causing a drop in United’s stock price, sparking calls for a boycott of the airline in China, and eventually forcing an apology from CEO Oscar Munoz and an offer of a full refund to all passengers on the fight.

Lawyers for Dao filed an emergency request Wednesday in an Illinois court seeking to preserve surveillance videos, cockpit voice recordings, passenger and crew lists, and other materials related to United Flight 3411, Reuters reported.

The CDA, meanwhile, explained the reasoning behind the original officer’s being put on leave in a statement released Tuesday evening.

“Aviation Security Officers (ASOs) are part of the public safety teams at both O’Hare and Midway, and complement and assist the Chicago Police Department (CPD), Chicago Fire Department (CFD) and federal law enforcement. While they do have limited authority to make an arrest, Sunday’s incident was not within standard operating procedures nor will we tolerate that kind of action. That is why we quickly placed the aviation security officer on leave pending a thorough review of the situation.”

Read more from Yahoo News: