The F.B.I. Deployed Surveillance Teams Inside Portland Protests

Senator Ron Wyden of Oregon, who has been scrutinizing the federal response to Portland, said in an interview that while federal officers have a right and a responsibility to protect federal property, there should be a high bar when it comes to agencies surveilling political gatherings.

“The Department of Justice needs to explain to me why it deployed those teams and provide a real record of their activities,” Mr. Wyden said. “What were they there for? Were they there primarily to chill peaceful protesters, or were they there to protect federal property?”

At the Inauguration Day demonstration in January, about 200 people gathered. “We are ungovernable,” one of their signs said.

Local and federal law enforcement records show that about half a dozen federal agents were there that day, with at least some of them doing what was described as surveillance in which they planned to follow protesters who engaged in property crimes or violence — even though the protest that day was starting on the east side of the city, far from the federal properties downtown. Agents singled out and tracked several people who had broken windows, trailing the individuals for several blocks until local law enforcement agents detained them.

Four agents testified before a local grand jury that was considering indictments against protesters who had been arrested. A person familiar with the proceedings said one of the agents testified that the federal officers had been wearing black apparel, a fact that suggests the agents were attempting to disguise themselves as protesters. F.B.I. officials declined to discuss specific tactics or clothing used during their operations.

Prosecutors obtained indictments for six people on riot and criminal mischief charges.

Mike German, a former F.B.I. special agent who specialized in domestic terrorism and covert operations and is now a fellow at the Brennan Center for Justice, said that such surveillance operations inherently run the risk of violating First Amendment rights. They should be used only when there is evidence that a serious crime may occur, he said, and they should be tailored to focus on obtaining the evidence needed to prosecute that crime.

“The F.B.I. should focus its resources on groups engaged in deadly violence, not vandals,” he said.

Mr. Cannon, the former F.B.I. supervisor in Portland, said the bureau was indeed worried about acts of violence directed at the police, the potential that the protests could escalate and the toll the demonstrations were taking on the Portland Police Bureau, whose officers were fatigued after months of near-nightly confrontations on the streets.