A second group of antiwar and anti-globalization protesters sued the District and its police department yesterday, repeating claims of earlier plaintiffs that the mass arrests in Pershing Park in September were unconstitutional, unnecessarily harsh and based on false charges.

The suit, which seeks class-action status to represent the more than 400 people arrested Sept. 27 at the downtown park, says that the "true purpose of the Pershing Park mass arrests appears to have been to disrupt and prevent political demonstrations," a violation of basic First Amendment rights.

"No one was breaking the law, no one trying to shut down the city, no one was trying to block the streets, no one was throwing bricks," said Arthur Spitzer, legal director for the local chapter of the American Civil Liberties Union, who is helping to represent the plaintiffs.

"Police can't arrest people because they think they're going to break the law at some point in the future," he said.

The arrests, made during a weekend in which some demonstrators vowed to cripple the city with waves of protests, have come under close scrutiny in recent months.

D.C. Council member Kathy Patterson (D-Ward 3) said in February that she had seen an internal police department report that concluded that officers on the scene never gave an order to disperse, though they herded more than 400 people onto police buses and charged them with failing to obey police orders.

The people arrested were left in handcuffs on the buses for more than 12 hours, detained at the police academy or in holding cells for several more hours and were sometimes bound by one wrist to the opposite ankle, according to the plaintiffs.

"We had been in drum circles for a couple of hours . . . when I saw the police surrounding us," said Mindi Morgan, 28, a Howard University student who is one of the plaintiffs. "I asked an officer if I could leave. He said, 'No.' I asked if I was under arrest. He said, 'No.' I asked if I was being detained. He said, 'No.' Then the buses pulled up and they started arresting all of us."

The five plaintiffs in the suit, ranging in age from 28 to 70, are represented by the local chapters of the ACLU and the National Lawyers Guild, as well as the D.C. firm of Covington & Burling.

They are seeking an unspecified amount of monetary damages and a court injunction to prevent police from making similar arrests.

Spokesmen for the city government and for the police department declined to comment on the suit yesterday.

Police Chief Charles H. Ramsey said in February that protesters had been ordered to disperse much earlier in the day, in part because they had no permit. Given the tense atmosphere at the time, he said, police officers' actions were justified.

"I certainly offer no apologies," Ramsey said then.

Yesterday's suit seems to mirror another case filed by different protesters in November. More than 20 plaintiffs, also seeking class-action status, sued the city, the police department, the U.S. Department of the Interior and the FBI over the same wave of arrests.

"We're already dealing with it," said Mara Verhedyn Hilliard, a lawyer with the Partnership for Civil Justice, a D.C. public interest law firm working on that case along with the national headquarters of the National Lawyers Guild.

Eventually the two suits, which are assigned to different judges, will be combined by court order or one suit will be dismissed, lawyers involved said.