He's trying hard to be inconspicuous -- a barrel-chested, crew-cut, bespectacled guy hanging furtively in the back doorway of a House committee room -- but David Bossie is impossible to miss. Dancing from side to side in his dull-gray suit, unable to suppress a tiny swagger, he looks a little like an overdressed Saturday night wrestler -- "The Destroyer" perhaps.

That, at least, is how President Clinton's friends would like to portray this 32-year-old college dropout and volunteer firefighter, the man who has become the nation's leading impresario of Clinton White House scandals. "Bossie is a pretty destructive fellow," says Clinton loyalist David Pryor, the retired senator from Arkansas. "I don't think I ever met him, but I never heard anything good about him. . . . His tactics are unconscionable, as far as I'm concerned, and I think he deals in a sort of cesspool world."

"He's something like a kamikaze," says Beverly Bassett Schaffer, the former Clinton-appointed chairman of the Arkansas securities commission who once accused Bossie -- along with a network television crew -- of "stalking" her on the streets of Fayetteville. "I think he's reckless. He throws bombs wherever he wants, and whoever's in the path between him and the enemy -- look out!"

Bossie -- who declined to be interviewed for this article -- lives at Firehouse 15 in Burtonsville, sleeping fitfully between alarms in a Spartan bunk bed. He ran 423 emergency calls last year, everything from delivering babies to dousing house blazes to cutting trapped victims out of car wrecks.

But he's far better known as the most visible investigator on Republican Rep. Dan Burton's Government Reform and Oversight Committee, the House panel probing Democratic campaign finance abuses. Burton, a staunch Indiana conservative who regularly denounces the Clinton White House for all manner of perceived perfidy, has leaned heavily on Bossie to rescue the embattled investigation and mount public hearings, including one scheduled for today. Bossie has been laboring mightily to lower his profile.

Fat chance. Not since Roy Cohn -- the bare-knuckled chief counsel for Sen. Joe McCarthy in the Red-hunting hearings of the 1950s -- has a congressional staffer been so thoroughly demonized by his enemies. And it has been a long time since a staffer stirred up such a fuss in Congress.

Although he joined Burton's staff last fall as chief investigator -- a post for which he's paid about $105,000 annually -- Bossie is now simply "a member of the investigative team," according to the majority counsel, Richard Bennett. Bennett is a new arrival to the committee; he started work in September after the committee's former counsel, John Rowley, left in July, along with two other staffers, following repeated clashes with Bossie.

Rowley's departure was highly public. His stinging letter of resignation, blast-faxed to the media, complained about "the unrelenting self-promoting' actions of the Committee's Investigative Coordinator," David Bossie.

According to committee sources, GOP Reps. Christopher Cox of California, Dennis Hastert of Illinois and Rob Portman of Ohio (none of whom returned a reporter's phone calls) pressed Burton to fire Bossie after Rowley's exit. At the time, Burton refused.

But with Bennett -- a former U.S. attorney of Maryland -- hiring a new chief investigator, veteran FBI agent Dudley "Butch" Hodgson, and sitting down for a beer with Rowley, there's increasing speculation among House Republicans that the chairman may soon be forced to drop the ax.

"I think they're wrong," says Rep. Christopher Shays (R-Conn.), a rare panel member willing to defend Bossie publicly. "I would say first of all that I like him a lot. I think he is a catalyst. He has creative ideas, energy, he's bright. I know he can be very aggressive and if you're his adversary, you may not like him. But he's making a contribution to the committee."

Rep. Henry Waxman of California, the committee's senior Democrat and a frequent critic of the panel's investigative procedures, is not so sure Bossie is doomed. He speculates that Bossie "must have Mr. Burton's full confidence because he decided to support Mr. Bossie and allow Mr. Rowley to leave."

Burton, for his part, refuses to comment on Bossie. "I really do not intend to get into a discussion about any of the committee's employees," he said last week.

Nevertheless, with the Senate's campaign finance investigation recently shut down, Burton's committee is taking center stage. Bossie is taking some heat.

"It's stating the obvious to say Bossie has an agenda, and that agenda is to take down Clinton," says a Republican Capitol Hill staffer who, like many who were interviewed, requested anonymity. "He's a decent guy, he's savvy, he generally knows how to deal with the press, he knows how to advance a story. . . . But the problem is, he leads with his agenda, and that drives everything -- and that just tends to undermine the credibility of the investigation."

"The climate has become extremely partisan -- really a polarized, poisoned atmosphere that has made it difficult to function on almost any matter," says Burton's predecessor as chairman, retired Pennsylvania congressman William Clinger.

Bossie's reputation precedes him -- and Clinton operatives work hard to assure that he never shakes it off. Since the 1992 presidential campaign, when he was a top official of the right-wing lobby Citizens United, publisher of the Clinton-bashing paperback, "Slick Willie" -- in which Citizens United president Floyd Brown called Bossie "the bloodhound who sniffed out many of the interesting stories enclosed" -- friends of Clinton have had Bossie in their sights.

He first came to national attention in a July 1992 report on the "CBS Evening News." It was not an auspicious debut.

Correspondent Eric Engberg reported that Bossie and a retired D.C. police officer, Jim Murphy, both working for Brown, had been harassing the friends and family of Susan Coleman, who had committed suicide years before. They were trying to confirm that Coleman shot herself "following a love affair with her law professor, Bill Clinton, that left her pregnant," Engberg reported. Bossie and Murphy trailed Coleman's mother to an Army hospital in Augusta, Ga., where her husband was being treated for a stroke. "Here the two men burst into the sick man's room," Engberg narrated, "and began questioning the shaken mother about her daughter's suicide." A chastened Bossie later told friends that the CBS story had made his grandmother cry.

Bossie decided to lighten up on sex and follow the money. During gumshoe trips through Arkansas in 1992 and 1993, he collected key contacts and documents regarding the Clintons' ill-fated Whitewater real estate investment and related problems. Throughout 1994, reporters -- including regulars from the major television networks and such establishment outlets as the New York Times and The Washington Post -- listened as Bossie held forth on the Clintons' complex financial entanglements.

"The Secret Spinner," Newsweek magazine dubbed him at the time. Bossie, who once toyed with the idea of becoming an investigative journalist, had by then developed an impressive reputation for honesty and accuracy among the mainstream press -- which made him unusual, if not unique, among ideological activists of any stripe.

"Dave Bossie has never lied to me, and the Clinton White House has lied to me," says ABC News producer Chris Vlasto, echoing the comments of other reporters. "If it comes down to a question of whom do you believe, I'd believe Bossie any day."

It was around this time that Bossie cemented his friendship with "Dan," as he and other senior staffers call Chairman Burton. Starting in March 1994, Bossie regularly fed the congressman suggestions for Whitewater speeches, which Burton then delivered on the House floor. Burton came to rely on Bossie's advice, once tracking him down by phone to Ocean City, Md., where Bossie was partying with some of his firefighter buddies.

In July 1995, Bossie took his anti-Clinton crusade to a bigger venue, becoming Sen. Lauch Faircloth's (R-N.C.) personal aide on the Senate Whitewater Committee. He was a conspicuous presence at the hearings, continually whispering in Faircloth's ear. "He's a very tenacious fellow, strong in his opinions, strong in his determination to get at the bottom of things," Faircloth says. "Let me say that we stayed pretty closely on top of what he was doing."

According to a Republican senator, Whitewater Committee Chairman Alfonse D'Amato (R-N.Y) was concerned from the start about Bossie's reputation for leaking. When unauthorized leaks did occur, this senator says, D'Amato admonished Bossie to "knock it off." Bossie, whether responsible or not, promised he would.

Richard Ben-Veniste, who was the Whitewater Committee's chief Democratic counsel, came away from the experience an unlikely Bossie fan.

"Because he was such a notorious bad boy, and because he had such an intimate relationship with the press, he became a lightning rod and was used to deflect attention from other leakers on the Whitewater Committee," Ben-Veniste says. "They frequently used the BDI defense.' BDI stands for Bossie Did It.' "

Ben-Veniste adds: "I like him. He was refreshingly candid. One of my beefs over a long career is hypocrisy, and Bossie is unvarnished and candid in his objectives."

"Under the tutelage and direction of about two or three people in Arkansas," says Clinton apologist James Carville, "Bossie is responsible for the greatest political dirty trick in American history -- this entire Whitewater thing. It's resulted in three congressional investigations, two special prosecutors . . . and it's all come to nothing. He made collective fools out of about 80 percent of the national press corps. I wish I was as skillful at manipulating the media as he is."

In fact, the Clinton people have done some skillful media manipulation of their own. A lengthy discussion of Bossie was a key element of last year's White House study of a so-called anti-Clinton "conspiracy" in the "media food chain" (this document, widely ridiculed, came to be known informally around the West Wing as "The Puke Stream"). The White House also prepared a dossier on Bossie that was distributed to reporters outside the Whitewater hearing room in February 1996.

The dossier included a fund-raising letter from Citizens United -- "the same people who are responsible for the Willie Horton negative attack advertisement {in 1988}," White House special counsel Mark Fabiani wrote in a cover note. In the letter, Floyd Brown claimed that "our top investigator, David Bossie, is on the inside directing the {Senate} probe."

Brown's letter prompted several Democratic senators to heap attacks on Bossie while a chagrined D'Amato ordered Bossie to swear in an affidavit that he was no longer employed by Brown's group.

Jane Sherburne, who was deputy White House counsel at the time, recalls being approached by Bossie in the hearing room as the Floyd Brown letter was having its desired impact.

"So how does it feel to get a little back?" the White House lawyer asked the Republican aide.

"You're not doing a bad job," Bossie replied.

"Thank you, I take that as a compliment.

"Well, you should."

Sherburne says today: "I kind of had to respect the guy."

Bossie knows hardball. When Roll Call reporter Mary Jacoby wrote a tough profile of him in early 1996, he made it his business to find out that Jacoby's father was a top executive in the Arkansas-based investment banking firm Stephens Inc., a company that figured prominently in the Whitewater probe. Then he set about spreading the news, resulting in a Robert Novak column suggesting that Jacoby had a conflict of interest.

More recently, Bossie has paid back Clinton loyalist Lynn Cutler -- now a White House aide -- for putting his photograph along with an unflattering biography on the Web site of Cutler's pro-Clinton organization, "Back to Business." The group recently disbanded, but the Burton committee subpoenaed the group's private donation records, which indicate a $25,000 contribution from the notorious Johnny Chung, one of today's witnesses.

"All I can tell you is that I've done nothing wrong," Cutler says.

Bossie was born in Boston, the second of four children of an X-ray technician father and a nurse mother, and grew up in Connecticut and Michigan before his family settled in Montgomery County. He attended Towson University and the University of Maryland but never graduated, neglecting his studies for the thrill of politics.

As an 18-year-old in 1984, he was smitten with Ronald Reagan and volunteered in the reelection campaign. Throwing himself into the College Republicans, he next worked against Rep. Michael Barnes (D-Md.) in 1986, and went on to become Sen. Bob Dole's Maryland youth organizer in the 1988 presidential contest. That was when he met Brown, a Dole organizer in the Midwest.

An accomplished political networker, Bossie snagged a job with Morton Blackwell after the presidential campaign, and arrived at Citizens United in 1991. He has been a volunteer firefighter for the past seven years. While he might discover that it's easier to put out a real fire than political one, some are betting on Bossie.

"I know Bossie by reputation as a hard case, a point man, a tough guy," says former congressman Clinger. "But sometimes you need to have a tough pit bull on your side." Special correspondent Anne Farris contributed to this report. CAPTION: The man behind the investigation: David Bossie, below and with Rep. Dan Burton at a news conference on the House probe into Clinton's finances. CAPTION: David Bossie at the Burtonsville fire station where, when not pursuing the campaign finance investigation as a GOP staffer, he's a volunteer firefighter.