Albrecht Gero Muth wore what he said was an Iraqi military uniform. (Sandy Schaeffer/(C) 2010 SANDY SCHAEFFER / MAI)

At parties and gatherings all around town, there are people you wonder about. It’s the guy who walks into the reception, hair slicked back, very Euro, tanned just enough to suggest a recent stay in Barbados. The woman with the shiny hair who air-kisses half the people in the room.

Who are they? Clearly the mystery guests must be important.

The question arises because of the apparent uncloaking of Albrecht Gero Muth, known, at least by some Georgetown neighbors, as the much-younger husband of 91-year-old Viola Drath. And now, far less amusingly, known as the man accused by police of killing her.

But the mystery guests of Washington are not always so sinister-sounding. Often an important-looking unknown will turn out to be a former under-undersecretary-of-something-or-other in the Carter administration or the widow of a foreign dignitary. Of an earlier era, perhaps, but not even remotely scandalous.

In the days before heightened security, a lot of mystery guests could be found at embassy functions such as a country’s National Day, said Mary Bird, who covers social events for the Georgetowner newspaper.

“In those days you could crash,” she said. And people did. “You’d see them up at the buffet, holding a large plate.” Recalling one couple she saw frequently, she added, “I don’t think they kept food at home.”

Eventually, some of those people might even get onto official guest lists.

“You create a persona,” said Bird, who has been on the Washington scene since the late 1960s, “and you keep it up, and pretty soon that’s who people assume you are.”

Carol Joynt, who writes the Washington Social Diary on the New York Social Diary Web site, agreed. “You don’t need to have a lot of cred in Washington,” she said. “A little bit of this and a little bit of that, then embellish it, and there you are.”

The obvious recent examples are Michaele and Tareq Salahi, whose alleged crashing of a White House state dinner led to public examination of their social embellishments. (Former Redskins cheerleader? The cheerleaders’ alumni group says no. Their charity event, America’s Polo Cup? Not so charitable, according to donation records.)

Why does such embellishment work? “I think Washington is still such a provincial town that we tend to believe people’s stories,” said Joynt, author of “Innocent Spouse” and former owner of the now-defunct Nathans restaurant in Georgetown.

Bird mentioned the self-creation of the late lobbyist and public relations man Edward Kloberg III, who styled himself as the Baron “von” Kloberg.

Referring to Muth’s habit of wearing what he said was an Iraqi military uniform, Bird said Kloberg “was a very similar kind of guy. He would bop into [Cafe] Milano swinging his cape” and wearing “two shades off of kabuki makeup.”

But Kloberg was fairly open about his posturing. His firm, Washington World Group, represented despots such as Saddam Hussein, Mobutu Sese Seko and Romania’s Nicolae Ceausescu. His glib tag­line, according to Post reporter Richard Leiby, who covered Kloberg’s suicide in 2005: “Shame is for sissies.”

Washington does seem to be a good place to reinvent yourself. Which is apparently what W. Nelson Lewis did before he was arrested in November following an incident on Capitol Hill. U.S. Capitol Police were called in response to an assault on a member of Congress, reported the Washington Examiner. The 26-year-old Lewis claimed to be Rep. Jack Kingston (R-Ga.) — with whom he had once had an internship — and, when that was shown to be untrue, was arrested for unlawful possession of a congressional pin (not Kingston’s).

He also claimed to be an ambassador for the Bahamas and a features writer for Rolling Stone, claims refuted by the country and the magazine.

But the Muth/Drath story has echoes that are closer to those of “Clark Rockefeller,” who turned out to be the German-born Christian Gerhartsreiter, convicted and imprisoned for kidnapping his daughter (currently under appeal) and charged with murder this spring in a 1985 Los Angeles death.

It’s important not to confuse the embellishers, the mystery guests — whom Joynt dubbed “the fringe” — with social climbers. The fringe “have their own scene, one that endures forever and is not dependent on a particular party being in power.”

David A. Deckelbaum is a real-estate settlement lawyer and native Washingtonian whose picture turns up frequently in Washington Life magazine coverage of charity parties. “I’ve always thought that Washington is a village, and if I don’t know somebody, I know who they are,” he said. “But it’s not true, it’s a horrible generalization: Washington is a village, but it’s also a city — and a transient city with people coming in all the time.”

That’s true, Joynt echoed: “Washington is an ever-changing pool of social life, with no boundaries.”