Actors, some of them anyway, like to play the parts of people totally different from themselves and different from the parts they've played before. They have terms for it, like "stretching," "playing against type."

Mark Harmon, the squeaky clean pitchman for Coors beer and former doctor on the "St. Elsewhere" staff, thought he was in for a long stretch when he took the part of Ted Bundy, a convicted mass-murderer on death row in Florida, sentenced in the killings of two coeds and a 12-year-old girl and suspected in 36 other sex slayings. Now, that's a stretch.

But then he found himself stalking women in the supermarket.

Harmon plays Bundy in "The Deliberate Stranger," a two-night, four- hour miniseries tight and Monday at 9. The story is based on the book Bundy: The Deliberate Stranger by Richard W. Larsen, a former Seattle Times reporter.

The drama, produced and directed by three-time Emmy winner Martin Chomsky ("Holocaust," "Attica" and "Inside the Third Reich") tells the story of the five-year manhunt for Bundy, suspected or convicted in slayings in California, Utah, Colorado and much of the Pacific Northwest.

The irony lies in the fact that Bundy, outwardly, is much like Harmon -- handsome, bright, charming and smooth, the sort of fellow women want to take home to meet the family.

As he got deeper into the Bundy character, Harmon began to lose touch with the part that most resembled him and got closer in touch with the dark side.

"I feel it's understandable that I'm not sleeping more than two hours a night," he said during a short break in the filming. "I had thought initially that the charming side of Ted Bundy was something that I was going to be able to find fairly easily and that the other extremes were going to be more difficult . . . Now, in week six of shooting, it's the charming side that's more difficult to find . . . It kind of gets in your head a bit."

Harmon, looking a bit haggard but very fit, said immersing himself into the part had kept him up at night. When that happened, he went running.

"People who have known me for 20 years come over to the house, take one look at me and turn around and leave . . . My dogs don't recognize me . . . This is make-believe, and I try to keep in perspective, but in a role like this, I find myself reminding myself more and more of that all the time."

Sometimes the reminding worked, and sometimes it didn't. Like when he might find himself "standing in a supermarket shopping and picking someone out and starting to play the stalking game. Certainly not to any kind of end or extent," he said, "but I've done that a lot, sure. It's not simple to try to understand this kind of disorder. I mean, it's not simple to say it's psychopathic or schizophrenic or sociopathic."

The line becomes fuzzy, of course, on whether he was talking about his or Bundy's disorder. Interviewed when work on "Stranger" was completed, Harmon said he was feeling fine and looking forward to chopping wood on a friend's place in Upstate New York to work off the accumulated tension.

"I'm shedding this part very slowly," he said three weeks after the shooting ended. "I'm sleeping nights, which is good. But it's still unsettling to talk about it."

Reflecting on his eight weeks as Bundy, he said, "I learned a lot about me . . . those different seeds that are in all of us, that we choose to let come to the surface. This role let me uncover some I wasn't too ready to admit were there.

"Chomsky was important," he added. "Our relationship was one of trust. I pushed it as far as I could and relied on him to pull me back."

After a bit of wood-chopping, Harmon wants to return to the stage for a spell. And what sort of play would he like to do? "I hope a light comedy."