The lawsuit by former officer James Long alleges negligence by the Chicago Department of Aviation because he was not trained to handle such a situation. It also claims that United Airlines acted negligently by “failing to foresee the consequences of its actions” when it called the aviation officers onboard.

The dragging incident sparked a huge outcry over the treatment of Dr. Dao, who suffered a broken nose and teeth, and a concussion while being forcibly removed from the plane. He had refused to leave after being randomly selected along with several other passengers to give up their seats on an overbooked, Kentucky-bound flight.

Video taken by passengers on board the plane went viral, creating a huge headache for United and the O’Hare International Airport’s police.

After being suspended following the incident, Long was fired in August, according to the suit. One other officer who was present was also fired, while another resigned.

The suit also alleges that Chicago Aviation Commissioner Ginger Evans defamed Long in tweets and remarks about the incident. Those remarks include tweets that Long was no longer a LEO (law enforcement officer), that the actions of the officers “were completely inappropriate,” and “We do not arm security staff for good reasons.”

Fortune contacted the City of Chicago and the city’s Law Department for comment, but has not heard back.

United was also accused of defamation for “implying that Long sexually harassed or criminally stalked Defendant Evans,” according to the suit.

In an email, a spokesperson from United told Fortune, “We have not been served with this suit and are unable to comment.”

The suit claims that Long, who has not found further employment, according to the Chicago Sun Times, suffered a “substantial loss of earnings, retirement benefits, and other employee benefits,” along with harm to his reputation and emotional distress. He’s seeking more than $150,000 in damages.

Last year, United reached a settlement with Dr. Dao for an undisclosed amount.