CHEYENNE - A report by the Wyoming chapter of the American Civil Liberties Union contends that the U.S. Forest Service has engaged in systematic harassment of people who attend Rainbow Family gatherings on public lands.

The ACLU opened an investigation this summer after a clash between members of the Rainbow Family - an informal group of self-styled hippies and peace activists - and U.S. Forest Service law enforcement officers.

About 7,000 members of the group attended its annual gathering this summer, which was held on the Bridger-Teton National Forest near Big Sandy in western Wyoming.

Forest Service law enforcement officers fired "pepper balls" - similar to paint balls but containing a pepper substance - at Rainbow Family members during the July 3 incident.

Scores of witnesses told the ALCU that the officers lacked justification, but the Forest Service said officers fired only after a crowd threw sticks and rocks at officers and otherwise interfered in the arrest of a man on drug charges.

The report also said that officers took the smallest violation as an excuse to search participants' cars and campsites for drugs throughout the gathering.

"This type of harassment and general overzealous enforcement appear to have been the pattern in the USFS relationship with the Rainbow Family," the ACLU report said. "The USFS has set up roadblocks, safety checkpoints, rolling gauntlets, and have searched and ticketed people on the narrowest of pretexts."

John Twiss, national head of law enforcement for the Forest Service, said Friday that he strongly disagreed with the ACLU's report.

"There's a lot of drugs at the gathering, a tremendous amount of drugs," Twiss said. "Which often leads to overdoses, violence, and a tremendous amount of problems."

Linda Burt, executive director of the ACLU in Wyoming, said her office interviewed about 60 Rainbow Family members who attended this year's gathering and reviewed court records of charges against members. The ACLU did not talk to Forest Service officials.

During the pepper ball incident, only one of the people the ACLU spoke with reported that they had possibly seen one person throw a stick at law enforcement. The rest said they saw nothing thrown, Burt said.

In an interview on Thursday, Burt said the ACLU is not planning to pursue legal action, but said she hopes Congress looks hard at the issue. The ACLU sent its report to members of Wyoming's congressional delegation.

"Certainly people do have that right to peaceable assembly under the Constitution," Burt said. "It doesn't state anything in the Constitution that only the 'right kind' of people can have peaceable assembly, or only the people who dress like we like to dress can have peaceable assembly."

Twiss was among the officers who responded to the disturbance at this year's Rainbow Family gathering. He described as "nonsense" the notion that Forest Service officers searched people or vehicles for drugs without probable cause.

The agency wrote only 18 citations for traffic and vehicle violations, but wrote 139 citations and arrested eight people for drug offenses, he said.

The Forest Service is discussing whether to allow future Rainbow Family gatherings on Forest Service lands, he said.

"Their behavior is unacceptable, and it's a tremendous financial burden on the tax payers to keep the gathering safe," Twiss said.

He estimated that it cost the Forest Service $1 million to patrol the Rainbow gathering in Wyoming this year. He said the group didn't share in the costs.

Garrick Beck, 58, of Santa Fe, N.M., was a participant at the Wyoming gathering. In a telephone interview Friday, he said he's been attending gatherings since 1972 and has seen increasing harassment from Forest Service law enforcement in recent years.

"I would say that the conclusion that there has been a consistent pattern of harassment is absolutely correct, and some of these consistent patterns have been extremely provocative," Beck said.

He said confrontations would escalate more if it weren't for the peaceful nature of the Rainbow participants.

Beck said he's been meeting with Forest Service officials in New Mexico this week to discuss possible sites for the group's annual gathering, which he said the group has decided to hold somewhere in that state next year.