"It's worse than sleazeball," said Stefan Presser, the ACLU's legal director. "This is an outrage."
Presser and other critics said dissenters needed the right to rally and to organize without fear that police were spying on them. They said they feared that police undercover officers could cross the line from intelligence-gatherers to provocateurs.
"The legality and propriety of this potentially unconstitutional police conduct will certainly be an issue at the time of trial in all of these cases," said Bradley Bridge, a senior lawyer with the defender's office.
During the convention, Police Commissioner John F. Timoney repeatedly denied that police had engaged in infiltration.
"We had not infiltrated any group," he said the day after police raided the warehouse that had become one of several gathering spots for demonstrators during the convention.
A spokeswoman for the commissioner said yesterday that he would have no comment. Lt. Susan Slawson, commander of the police public-affairs unit, said the commissioner could not talk because "it's in litigation," a reference to a civil suit filed by demonstrators challenging their arrests during the protests.
The use of state police as the undercover operatives took place as the city itself was restricted from using its own officers for such infiltration under a long-standing mayoral directive. The directive says the police may not infiltrate protest groups without the permission of the mayor, the managing director, and the police commissioner.
Mayor Street and City Solicitor Kenneth Trujillo declined comment yesterday.
In seeking search warrants, police cited the work of the undercover operatives and detailed the intelligence gathered as the convention approached. The information is sketched out in affidavits of probable cause seeking warrants to search the warehouse, a U-Haul van, another van, and a pickup that police deemed suspicious.
"This investigation is utilizing several Pennsylvania state troopers in an undercover capacity that have infiltrated several of the activist groups planning to commit numerous illegal direct actions," said one affidavit, signed by Detective William Egenlauf of the Philadelphia Police Department.
It says the state police undercover operatives arrived at the warehouse on July 27, four days before the convention began.
Once there, the agents assisted "in the construction of props to be used during protests," the affidavit says.
It says agents observed demonstrators building street barriers and "lock boxes," devices used by protesters to lock arms together when blocking streets. The papers say they overheard discussions that indicated protesters planned on "using the puppets . . . as blockades."
The operatives also reported that "persons indicated they would be throwing pies, bottles and cardboard boxes filled with water at the police," the affidavits stated.
Timoney held a news conference after the convention to display items seized during the raid, including two massive slingshots and chains wrapped in kerosene-soaked rags. Such devices were not used during the protests. Police also displayed seized "lock boxes."
Protesters have claimed the facility was nothing more than an art studio to fashion the puppets, floats and other props that were a hallmark of the demonstrations.
Demonstrators also said their protests would be nonviolent, with illegal actions limited to the blockading of streets. Their lawyers have complained that numerous people were arrested in the warehouse without any proof they had any connection to illegal items.
A key subject of controversy has been the raid on the warehouse.
The request for the search warrants for the warehouse and lengthy affidavits detailing police intelligence-gathering was made yesterday, a month after Municipal Court President Judge Louis J. Presenza approved the searches.
At the request of the District Attorney's Office, the warrants were sealed - barred from public inspection - for a month as soon as they were issued. The legal request for the warrants maintained that premature "disclosure of this affidavit could endanger the lives" of the undercover operatives.
The affidavits cite sweeping police intelligence-gathering before the convention. This included monitoring of unspecified "electronic messages" sent among demonstrators, an apparent reference to police scrutiny of Web sites and electronic mailing lists.
The police documents identified what investigators viewed as the key protest groups and their goals. Funds for one group "allegedly originate with Communist and leftist parties and from sympathetic trade unions" or from "the former Soviet-allied World Federation of Trade Unions," according to the affidavits.
The affidavits go on to identify a handful of leaders of the various groups. Among those cited by name are John Sellers and Kate Sorensen, who were later arrested during demonstrations in Center City. The two were held in jail for days in lieu of $1 million bail - a sum critics said was extraordinary. In recent interviews after their release from jail, people who were inside the warehouse said that they had suspected early on that four undercover officers were working among them. Four men - known as Tim, Harry, George and Ryan - showed up together at 41st and Haverford about a week before the convention, introducing themselves as union carpenters from Wilkes-Barre who built stages, several demonstrators said.
They were big, burly men who were older than most of the people working in the warehouse. They did not seem particularly political or well-informed, according to demonstrators. All four, however, were considered hard workers.
Soliman Lawrence, 20, of Tallahassee, Fla., worked closely with the four on a massive satirical float built for a protest march.
"They gained our trust," Lawrence said. "The fact that we didn't know them very well wasn't a big deal.
"I remember thinking to myself, 'Why does everyone who looks like that have to be a cop?'" Lawrence said. "I didn't like that I thought like that."
Linda K. Harris' e-mail address is firstname.lastname@example.org