A St. Mary's College of Maryland student has filed a lawsuit in federal court in Greenbelt, alleging that his civil rights were violated when he was pepper sprayed by a sheriff's deputy and falsely arrested during a back-to-school party last year that brought police, a helicopter and dogs to the campus of the small liberal arts college.

Attorneys for the Maryland chapter of the American Civil Liberties Union filed the lawsuit on behalf of Kenneth Daryl Knight Jr., 21, of Lexington Park, who says police actions on the night of Sept. 5, 1998, constituted false imprisonment, assault and denial of medical treatment, among other allegations.

St. Mary's County Sheriff's Deputy Eric S. Walker, the sheriff's department and two unnamed deputies were listed as defendants in the lawsuit, filed in U.S. District Court. Knight is seeking unspecified damages for his injuries, the cost of litigation and compensatory damages.

"The plaintiff was clearly wronged here, in terms of use of any force against him, much less pepper spray, which is not a benign chemical. He suffered severely when he was sprayed," said David H. Coburn, an ACLU member and a Washington attorney who is representing Knight.

"His civil rights were clearly violated," Coburn said.

On Labor Day weekend last year, hundreds of students gathered for a back-to-school party at the Townhouse Green, a scenic campus lawn shared by dormitories for senior students. Some of the students were drinking beer, an apparent violation of a no-alcohol policy on campus. But many students said the party was not rowdy or out of control.

The students failed to disperse when campus security initially tried to break up the party. A call for assistance brought state police, sheriff's deputies and even police from the Patuxent River Naval Air Station descending on the tiny campus with a helicopter and police dogs.

In court papers, Knight repeated what he has told reporters and investigators: He and a friend, Ashley Larrimore, 22, a student from the University of Maryland at College Park, were preparing to leave the party as ordered by another deputy, Christopher Medved, who is not a defendant.

But as Knight walked to his truck, he said, Deputy Walker approached him and Larrimore, threatening to spray them with pepper spray if they didn't leave.

"Plaintiff Knight responded by holding up his hands with his palms open in order to demonstrate that he was not carrying anything that would threaten Defendant Walker, and stating, 'Don't spray anybody. We're leaving,' or words to that effect," the lawsuit said.

"Defendant Walker replied, 'Oh, yeah?' and sprayed Plaintiff Knight with . . . pepper spray," the lawsuit said.

Walker arrested Knight for disorderly conduct. Larrimore was not arrested. In all, police arrested 17 other students during the confrontation.

Knight's lawsuit alleges that he was denied water and medical care for the next few hours even though he "was in visible distress, spitting and coughing with mucus discharging from his nose."

Knight, who is now a senior at the college, this week declined through one of his attorneys to comment on the lawsuit.

But in an interview with The Washington Post earlier this year, Knight said, "I did nothing wrong. None of this should have happened in the first place. We were leaving. I was about 15 feet from my truck when I got pepper sprayed. It came out of nowhere."

Knight said he was locked in a cell overnight. A breath analysis confirmed his statement that he wasn't drinking alcohol at the party. His lawyers said he suffered acute dermatitis, or severe skin inflammation.

Walker did not return a telephone message left at the sheriff's office in Leonardtown.

Sheriff Richard J. Voorhaar said Tuesday that he was unaware of the lawsuit had been filed, but defended the actions of his department and deputies.

"We reviewed everything the deputies did down there and we found no improprieties as to their actions," Voorhaar said. "They showed tremendous restraint in dealing with a difficult situation. I have no problem with what they did down there."