By now, you've seen the horrible video of Dr. David Dao being dragged off a United Airlines Kentucky-bound plane. Today, United received bad news: Dao has filed court papers demanding that the company preserve all evidence.

By filing an emergency "bill of discovery" against the carrier in Illinois State Court, Dao and his attorneys are laying the groundwork for a legal battle. The order will force United Airlines to preserve all evidence, including surveillance videos, cockpit voice recordings, passenger and crew lists, incident reports, and other related evidence. In filing the paperwork, Dao's attorney argues that "serious prejudice" will befall his case if evidence is not preserved. During a Thursday news conference, Dao's attorney said that he will "probably" sue the airline. It was revealed that Dr. Dao suffered a significant concussion, a broken nose, sinus injury, and lost two front teeth. On Sunday, Dao was one of four passengers randomly chosen to be re-accommodated to make room for United personnel to be seated on the full aircraft. When Dr. Dao refused, citing patients he needed to see the following day at the hospital, United employees sent in Chicago Aviation police officers to forcefully remove him from the plane. Passengers captured Dao being bloodied and dragged off the airplane. Within minutes of being removed from the plane, Dao escaped police custody and re-entered the cabin. Disoriented, he walked down the aisle looking for a seat before he was removed a second time.
We learned on Thursday that Dr. David Dao has no recollection of ever returning to the cabin, likely a result of the concussion he received during the struggle. The Chicago Aviation police officers involved in the incident have been suspended pending an investigation. After initially refusing to admit wrongdoing, United Airlines lost $1.4 billion in its valuation at the height of the scandal. Since then, the company's CEO has admitted the incident was a mistake and United's stock has mostly recovered.