In her quest to stop a ballot initiative to legalize slot machines, Dorothy Brizill arrived at the D.C. Board of Elections and Ethics headquarters last week armed with a tape recorder, a laptop computer, a legal pad, a box of files, a copy of the D.C. Code -- and a bombshell for her opponents.

Using the words "alarming," "dramatic" and "chilling," Brizill stated before a room full of board members, lawyers and reporters that two city residents had called her to report that they had been harassed and intimidated by slots advocates.

John Ray, the lead attorney in the campaign to bring slot machines to the District, immediately labeled Brizill's allegations "outlandish." He took off his glasses, wiped his face and sighed heavily. Moments later, he lost his cool entirely.

Brizill's statements were "designed for the press," Ray told elections board Chairman Wilma A. Lewis. "Don't let her get away with it."

Newspapers the following day carried accounts of the alleged harassment.

As many have before, the people trying to bring slot machines to the District have discovered that their most significant hurdle may not be a city leader or a lawyer but rather Brizill, 56, the super-activist and government watchdog.

Backed by a coalition of supporters, Brizill challenged the legitimacy of thousands of petition signatures filed by the slots proponents in an effort to get their initiative on the Nov. 2 ballot. Brizill's group contends that the petitions are marred by widespread forgery and fraud.

The case has not been easy. Brizill said she has spent $800 of her own money on documents, was accosted by police while videotaping petition circulators and has worked 16-hour days during the election board's hearing on two challenges to the slots petition drive.

"It's tiring and not always rewarding, but you can stand back and say you do make a difference, we as a group make a difference," Brizill said in a brief interview in a hallway outside the hearing room. "It keeps your batteries charged for quite a while."

A full-time gadfly, Brizill and her husband, Gary Imhoff, publish a good-government Web site, www.dcwatch.com. Brizill shows up prepared for news conferences and public hearings -- with reams of papers in her arms and gold-rimmed reading glasses perched on the tip of her nose.

She can be indignant, pedantic and temperamental, say those who have worked with her. She elicits a mixture of respect and frustration from city leaders.

"Sometimes I want to jump over this podium and strangle her," Mayor Anthony A. Williams (D) said. "But as annoying as she is, as aggressive as she is, the city is better off overall because of that kind of citizen oversight."

Two years ago, when the mayor was seeking reelection, Brizill made an issue of irregularities in his nominating petition and got him tossed off the Democratic primary ballot. Forced to wage an expensive write-in campaign, Williams won, but he emerged chastened.

A Williams fan when he was the city's chief financial officer, Brizill now says the mayor is "very distant and very disrespectful of citizens."

"A lot of things he just wants people to accept," Brizill said of Williams. "I think I challenge him. And I thought I challenged him to be a better mayor, and I think he takes my challenges as arrogance and in-your-face."

Brizill grew up in Queens, N.Y., the daughter of a plumber and stay-at-home mom. She studied political science at Queens College and received a master's degree in international affairs from Columbia University.

In the 1970s, she moved to Washington and worked as a special assistant to Warren M. Christopher, who was deputy secretary of state in the Carter administration. Later she commuted between Washington and New York to work as a foreign trade adviser to then-Gov. Mario M. Cuomo (D).

Her local activism began with a drive to rid her Columbia Heights neighborhood of drug dealers. Her efforts sparked reforms in the city's housing inspections unit. Before long, she was a full-time activist, and she helped launch a federal probe into whether then-Mayor Sharon Pratt used city employees to raise money for her reelection campaign in the mid-1990s. Investigators later ruled that some campaign workers violated federal laws.

Brizill met Imhoff after hearing that there was a room for rent at the house where he lived. She decided not to move in, but he asked her on a date. They've been a formidable pair ever since.

Opposites in some respects -- Imhoff is more easygoing as suggested by the photo of Cary Grant he posted next to his name on their Web site -- the two share a passion for hound-dogging government. In recent weeks, they have been so busy that Imhoff has had no time to fix his eyeglasses, whose right stem broke off weeks ago.

Neither holds a regular job. They have said they operate D.C. Watch and themail, a twice-weekly e-mail newsletter, with money Imhoff inherited and mutual fund dividends. Brizill generally patrols city hall, while Imhoff acts in a supporting role from home.

"Every city I've been has someone in a role like hers, but she brings a higher level of intellect and knowledge of how District government runs," said City Administrator Robert C. Bobb, who arrived last year from Oakland and was taken to his first community meeting by Brizill.

Some say Brizill, who ran unsuccessfully for the Ward 1 seat on the D.C. Council in 1994, is not an idealist but a frustrated would-be politician. Others complain that she blurs the lines of journalism and activism to promote her own causes.

Brizill takes umbrage with such criticism.

"My concern goes to the city," she said. "They try to make it personal. They just do not get it. . . . I'm the easiest person to read. What you see is what you get. Yes, I get angry. Yes, I get passionate. Yes, I work hard. But there's no ulterior motive."

Ray, the lawyer and a former D.C. Council member, is among those skeptical of her motives. He pointed out that when the elections board decided to hear lawyer Ronald Drake's challenge of the slots initiative before Brizill's, Brizill insisted on sitting at the table with Drake.

"Dorothy likes the limelight, and it's really more about that than about being a watchdog," he said.

Brizill scoffed at the suggestion. She said that she and Drake had become allies in the anti-slots coalition, which made her its primary spokeswoman.

The Rev. David Argo, a Methodist minister who has joined the fight against slots, said Brizill was best able to lead the effort.

"She consistently knows who needs to be contacted," he said. ". . . When we did our presentation in Superior Court, she held her own against the attorneys. I'm glad I'm on her side."

"It's tiring and not always rewarding, but you can stand back and say you do make a difference," Dorothy Brizill said of her efforts.Brizill denies seeking out the limelight: "My concern goes to the city."