Business is bad for Fairfax County homicide investigators these days but, given their business, nobody's complaining.

As of today, the six-man unit responsible for murder cases in the county of 649,000 people hasn't had a homicide in six months.

The last was a stabbing death Dec. 14. No one on the homicide squad or at the Fairfax Courthouse can recall a period in which so much time has elapsed without a reported killing, and there certainly hasn't been such a stretch in the last decade. The county averages one homicide a month, and last year at this time there had been eight.

"Our only problem with talking to you about this, of course, is that you're jinxing us," said criminal investigations chief Maj. Michael Young with a grin. "As soon as we talk to you, we're going to have one."

That sort of superstition has become routine in the unit. Every Friday there are jokes to the weekend on-call investigators that "this is the weekend."

"It actually feels like there's a little more pressure," said homicide Investigator Bruce Barley. "We know it's coming; we just don't know when. At least when we're busy, we don't have time to think about the next one."

"I think it's wonderful," said Fairfax County Prosecutor Robert F. Horan Jr., adding, "I wish we had the magic answer to the question 'why?' If we did, then we could go out there and deliberately create this sort of situation."

Whatever its source, the magic this year is entirely local. Homicides are up in Prince George's and Montgomery counties, and holding at about the usual level in Alexandria, Arlington and the District of Columbia.

No one in the police station or the courthouse takes credit for Fairfax's lack of slayings.

"When I retire, I'll write a book and tell you how we did it," joked Young.

"I don't take credit when the crime rate goes down," said Horan, "because I sure as hell don't want the blame when it goes back up. I wish I could tell you that it was something we were doing in this office that did it, but I can't."

The homicide squad hasn't been altogether without work.

Indeed, the courthouse crowd has renamed it the "suicide squad," because while the reported slaying rate is nonexistent, the suicide rate is up 90 percent from 1984.

Fairfax County's homicide squad investigates all suspicious deaths, all suicides, all adult missing persons cases and many serious aggravated assaults -- none of which has shown any sign of abating.

Two homicide detectives have been assigned full time to the double slaying of Morton and Sylvea Grossman in their McLean home in October 1981.

Although there have been no reported homicides in six months, there have been several close calls -- a man stabbed in the skull with a screwdriver, a 2-year-old girl shot twice by her mother before the mother committed suicide.

"In several cases, it was just a matter of divine intervention that people haven't died," said Young.

"I don't think there is anything in the external world that controls it," said Horan, "not the economy, or the phases of the moon, or anything like that.

"Unfortunately, I know the phone call is going to come one of these days, between 1 a.m. and 3 a.m.," said Horan. "And it's going to be Fairfax homicide, and they're going to say, 'We got one.'

"Like the man in the Bible says, 'I know not the day nor the hour,' but I know sure as hell I'll get that call."