In the spring of 2006, Anne Havemann placed a call to the National Oceanic and Atmospheric Administration to make arrangements for a meeting at their headquarters in Rockville, Md. As public affairs director for the Chesapeake Climate Action Network, she had been assigned to organize a press conference coinciding with the first day of the hurricane season to discuss the link between global warming and powerful tropical storms.

After a few phone calls and e-mail exchanges with Maryland State Police and Department of Homeland Security staff, Havemann acquired the permits, and the press conference went off without a hitch. But two years later, and much to her alarm, Havemann learned that as a consequence of this innocent transaction, her name had been entered into a criminal activity database by Maryland State Police and tagged with the label "terrorist/environmental-extremist."

CCAN describes itself as "a grassroots, nonprofit organization dedicated exclusively to fighting global warming," and its name shows up frequently on the Web in relation to events in the Maryland and Virginia area that feature citizen input on environmental issues, from opposing new coal-burning power plants to a fundraising Polar Bear Plunge.

Havemann says she has no connection with terrorism or any other illegal activity — in her words, "not even a speeding ticket." Nevertheless, Maryland State Police targeted her for surveillance along with more than 50 other apparently law-abiding citizens whose names had been associated with the terrorism tag in a federally funded database.

The surveillance was part of an undercover police operation that came to light when documents containing hints of spycraft on the part of police surfaced during pretrial discovery in an unrelated case.

Using Freedom of Information requests to dig deeper, lawyers with the American Civil Liberties Union unearthed a snooping program that spanned — at a minimum — 2005 through 2006 and that had targeted advocacy and activist organizations devoted to a range of causes — for peace, against the death penalty, for the environment — falling roughly on the left side of the political spectrum.

In July 2008, Maryland Gov. Martin O'Malley assigned former state Attorney General Stephen Sachs to review the surveillance program. According to Sachs' critical 149-page report, while the department cooperated fully with his efforts, key high-ranking officials declined to comment for the report. Lower ranking police operatives, however, admitted to infiltrating activist organizations while posing as sympathetic participants and using fictitious identities to attend, and offer input, during the targeted groups' organizational meetings.

The report says that officials also admitted to monitoring the groups' electronic communications and befriending activists, chatting with them about art and social engagements while eliciting information about their organizations' plans — in essence, employing tactics one might expect from those investigating organized crime, drug trafficking or life-threatening conspiracies.

Havemann said the subterfuge was unnecessary.

Despite having been spoofed into addressing e-mail messages directly to a Yahoo online account maintained by undercover police, she said the police would have received the same information had they signed up with their actual names, as representatives of the police department. "We have nothing to hide," she said. "Nothing we do is secret, and we're happy to share information about global warming and the environment with anyone who signs up for our e-mail list."