GREAT FALLS, Mont. (AP) – The Fort Peck Tribe and Wolf Point-area law enforcement agencies conspired to illegally round up homeless people in July 2013 to prevent them from panhandling during a rodeo and parade weekend, according to a civil complaint filed on behalf of 31 Native Americans.

The lawsuit, filed Monday in U.S. District Court in Great Falls, says up to 50 people – including two who are disabled – were handcuffed, hauled to jail in crowded vehicles, held in inhumane conditions overnight and released the next day without charges being filed.

The plaintiffs are seeking damages for physical and emotional injuries and civil rights violations resulting from the mass arrest and detention during the Wild Horse Stampede. The complaint names the Wolf Point police chief and city council, two Bureau of Indian Affairs agents, several tribal officials and the Roosevelt County sheriff and county attorney.

“The (tribal) Law and Justice Committee told the police officers . ‘Do something about these homeless street people during the Wild Horse Stampede Rodeo,' " Mary Cleland, a tribal court lay advocate who is assisting the plaintiffs, told the Great Falls Tribune. “They didn't even issue any paperwork. They verbally told the captain of the police, ‘Get them out of sight. Put them anywhere, and don't charge them.' "

Officers “just went around grabbing people like they were animals,” Cleland said.

Floyd Azure, chairman of the Fort Peck Tribal Executive Board, did not immediately return an email from The Associated Press on Wednesday seeking comment on the allegations.

The men and women who were detained were placed into two outdoor recreation areas surrounded by a chain link fence after the jail in Poplar became full, the complaint said.

The detainees did not have adequate food, water, toilet facilities or medical care, the complaint said. The jail's water and sewer system was under repair at the time.

“That day was hot,” Cleland said. “People were passing out from heat exhaustion. They were not fed properly and they were not given mattresses or jail uniforms. They went in their street clothes and they just threw them in there like dogs in a chain-linked exercise court exposed to the elements.”

Jail staff reportedly tried to mitigate the heat by covering a portion of the exercise yards with large plastic tarps but a thunderstorm tore the tarps and exposed them to rain. The women were eventually held in the detention center overnight while the men were housed in a garage. They were released the next morning.

Cleland said the Bureau of Indian Affairs investigated in April 2014 and found multiple violations, but nothing was done to remedy the abuse. Special Agent Angela King declined to comment on her investigation. BIA spokeswoman Nedra Darling did not immediately respond to an AP request for comment on King's findings.

The complaint said there were people who knew ahead of time of the planned roundup and did nothing to stop it.

Anna Rose Sullivan, city attorney for Wolf Point and the deputy Roosevelt County attorney, told the newspaper she could not comment because she had not seen the lawsuit, but said officials are taking the allegations seriously.