GRANTS PASS, Ore. — An undercover informant helped investigators tape a conversation with one of the seven alleged radical environmentalists accused in a series of arson attacks and other crimes in the Pacific Northwest between 1998 and 2001.

Existence of the informant was disclosed last week by an investigator in U.S. District Court in Brooklyn, N.Y., during a bail hearing for Daniel McGowan, 31, who faces indictments that he and another man firebombed the office of a wood products mill in Glendale and the office and truck shop of a tree farm in Clatskanie in 2001.

The Earth Liberation Front, an underground group that advocates economic sabotage to stop environmental destruction, took credit for the two fires. The FBI describes the group as one of the nation's leading domestic terrorist organizations.

Though his family offered to put up their homes and stocks worth about $850,000, McGowan was ordered held without bail pending transport by U.S. marshals to Oregon, said defense attorney Martin Stolar. No date has been set for McGowan's arraignment in Eugene.

Assistant U.S. Attorney Stephen Peifer, who attended the hearing, said Eugene police detective Greg Harvey testified he made the tape from a body wire worn by an informant who talked to McGowan at a convention in New York in April 2005. On the tape, McGowan talks about going to British Columbia in 2001. The tape was not played in court, but the judge listened to excerpts before deciding against granting bail.

Peifer characterized the trip as hiding out after the arsons, both of which occurred earlier that year.

Stolar and McGowan's sister, Lisa McGowan, the vice president of a packaging company in New York, characterized the trip as a visit to a couple of friends and their new baby outside Vancouver, B.C. He crossed the border using his own passport, and his family knew where he was, his sister said. He later went back to Eugene for a while before moving to New York in 2001.

"If anybody was looking for him, Danny was not a hard person to find," Lisa McGowan said.

He took part in protests during the Republican National Convention in New York in 2004, was included, under an assumed name, in a Rolling Stone article on those protests, and was working for the Women's Law Initiative in Brooklyn, which helps abused women, at the time of his arrest, his sister said.

Lisa McGowan said her brother knew the person wearing the hidden microphone from his days as a political activist in Eugene, where he had lived a few years before moving back to New York four years ago.

"From what I understand, my brother states the atmosphere in Eugene was very tough to live in at that time," for political activists, she said.

In late 1999, a number of anarchists from Eugene had taken part in riots against the World Trade Organization meetings in Seattle, and authorities were clamping down. Anarchists also clashed with police in Eugene.

"My brother does not state he was involved in any of these things. He did not state he was running from anybody. Just that he was laying low because the atmosphere was very tough in Eugene at that time," Lisa McGowan said. "They wanted Danny to say he was involved. Danny didn't say that."

Lisa McGowan said her brother worked in a cafe frequented by political activists while living in Eugene and was regularly confronted by police who knew him by name, often while he was riding his bicycle.

"Being an activist doesn't mean you are a criminal," Lisa McGowan said. "My brother has his beliefs. We are proud of the things he fights for.

"The weird thing was if Danny was asked to come in for questions he would have shown up and answered any questions," she said. "But he wasn't. They burst into his job. He works for a law firm — not for profit — that helps abused women. They kind of burst open the door, cuffed him and took him."

The youngest of five children of a retired New York City transit police patrolman and a housewife, McGowan was born in Brooklyn, N.Y., but grew up in Rockaway Beach in Queens, where he ran track at Christ the King High School, Lisa McGowan said.

He graduated from State University of New York at Buffalo with degrees in history and business, and traveled after college to Thailand. Later he lived in San Francisco, then Eugene, before moving back to New York City, where he lives in the East Village.