If you tried to sell a TV producer on a story you'd made up about a man who persuades his daughter and sister-in-law to kill his wife, you'd be laughed out of the room. Or, say, if you came in with a yarn about a serial rapist who is dominated by his mother. Thanks, but no thanks.

But rush to the same producers with a headline torn from the day's newspaper, or a hot-selling book detailing some macabre relationship, and you could count on a quick sale.

Welcome to the world of the fact-based TV drama, or docudrama, the TV format increasingly being counted on to fill network time.

In the middle of a February sweeps that has been peppered with such fare, CBS and NBC trot out two such fact-based dramas this week. They both explore the seamy side of life. They are filled with one lurid (within network bounds) detail after another. They both deal with awful people doing awful things. If you watch these shows, you'll feel guilty in the morning (at least, you should). They are guilty pleasures indeed.

NBC opens the week with "Love, Lies and Murder," a two-night, four-hour miniseries (Sunday and Monday at 9). The show deals with a 1985 murder in California in which 14-year-old Cinnamon Brown (played by Moira Kelly) was convicted in the slaying of her 22-year-old stepmother. John Ashton plays an investigator from the district attorney's office who is not satisfied that all the facts are known. What about the involvement of the victim's younger sister? The sister, Patti Bailey, is played by Sheryl Lee -- to be forever remembered in TV history as "Twin Peaks'" Laura Palmer.

When Cinnamon offers a different version of the killing three years later, attention is focused on her father, David Brown. David Brown is played by actor Clancy Brown in a portrayal that is at first annoying -- his speech pattern is truly grating -- and finally riveting as the story of his masterful control of the three principal women in his life unfolds. He comes off as a house-broken Charles Manson.

If four hours of Brown's manipulation isn't enough, there's CBS's "Sins of the Mother" Tuesday at 9. Here the manipulation is in the hands of one of television's enduring stars, Elizabeth Montgomery, who's still asked by fans to do the Samantha nose twitch, the trademark of her "Bewitched" series.

Beneath her smooth exterior lies a woman in tight control of the two men in her life, her husband, played by Richard Roat, and her oil-slick son, Dale Midkiff. Faced with his mother's obsession, Midkiff's character's basic coping mechanism is to become a serial rapist.

If this kind of show isn't your favorite thing -- or if overindulgence in televised war news has dulled your appetite for fact-based TV fare -- then you'll have a lot more free time this spring. A number of vehicles the networks are counting on to draw viewers this month and during the May sweeps are docudramas. Warren Littlefield, president of NBC Entertainment, estimates that 40 percent of his network's inventory is made up of such programs.

A growing number of these dramas seem to deal with bizarre crimes committed by the socially depraved. For Beth Polson, a highly respected executive producer and the force behind "Sins of the Mother," the trend is simply a matter of the network's trying to catch up with viewers' tastes.

"The audience always takes the lead in these things," she said. "The network in some ways is playing catch-up with the audience. Wherever the numbers go," she said referring to TV ratings, "you try to follow that trend ... I don't think it's the networks' fault. The audience really dictates what we give them."

Polson acknowledged that as a former journalist, she can get excited about intriguing clippings. "I'm still kind of a news groupie," she said. "And I became interested in this story when it was a two-paragraph story in the newspaper."

But "Sins" is a far cry from the type of material she's identified with. Polson may be part of the glut of sociopathic stories, but she's hardly responsible for it. Her TV movies have included "Go Toward the Light," "Baby Girl Scott," "Not My Kid," "Guess Who's Coming for Christmas" and "This Child Is Mine."

"I'm much more likely to still do the kinds of Humanitas nominees that I like to do," said Polson. "But I can tell you, they're very hard to sell."

In the face of their declining share of the TV audience, networks have been looking for ways to lure people back from cable and VCRs. "I think the audience does respond to true stories," said Polson. "And the networks, as we all know, right now are trying to find what the new formula is for the audience, because we're all worried about what network television is going to become and what we should be doing to fill that need.

"The audience has a certain curiosity about true stories. This is my first crime story, I have to say. So I'm definitely part of the glut. But to me, this is a human drama. I wasn't particularly interested in this as a rape story. What interested me was the psychological drama ... this love-hate obsession between the mother and son."

Robert Markowitz, director of "Love, Lies and Murder," has worked on both gentle TV movies ("Decoration Day") and tough ("A Cry for Help: The Tracey Thurman Story," a fact-based tale of extreme wife abuse). To him, these terrible stories are a chronicle of the breakdown of the American family.

"With all the perversions that go on and all the other illnesses in our family, I think that's why these films keep happening," he said. "And I think that's why people keep watching them. I think they all want to know the answer to that question ... How did the American family so break down that we are faced with this day after day?"

"Love, Lies and Murder," he suggested, is a cautionary tale. "The audience can learn about parental responsibility, the dangers of manipulation, the dangers of not listening to your children when they're speaking from pain, the dangers of not paying attention to what's going on in the house next door."

But viewers are far more likely to watch simply in morbid fascination than they are to turn in the guy next door. And while such dramas inundate the viewer with details about the lives of the strange people being depicted, it's an open question whether we really come to any deep understanding. We watch, but do we learn?

Meanwhile, there could be another fact-based family drama brewing in Texas. That's where it was recently reported that a mother, fearing her teenage daughter might be beaten out for the last slot on the cheerleading squad, took matters into her own hands. In an effort to create a distraction for her daughter's chief rival, she allegedly tried to hire a hit man to kill the other girl's mother. Look for it during the November sweeps.