Barefoot and in blue jeans, his gut protruding from a sleeveless shirt, 45-year-old Scott Schultz knew what was coming the moment he saw Santa Clara County DA's investigator Mike Schembri walking up the sidewalk to his home in Loveland, Colo.

``Mike, I told you the truth! I told you the truth!'' Schultz yelled in a last attempt to assert his innocence. The tears in the corners of his eyes betrayed his feelings. The baldish motorcyclist knew Schembri was there to arrest him on suspicion of killing his high school girlfriend from Los Altos, Laura Anne Beyerly, 28 years ago.

The 57-year-old Schembri, a onetime college pitcher who hides an athlete's competitive instincts behind an unassuming 5-foot-9 build and a Brillo pad of neatly trimmed gray hair, doesn't come across as Inspector Javert stalking his criminal prey.

The veteran investigator strikes even the bad guys as more of a father-confessor figure, a man you want to confide in. But mark down humility as one of his most lethal assets. ``I'm not the best,'' he says. ``I've seen the best. I just work hard.''

If Schembri is not the best investigator in Santa Clara County, his colleagues say he's one of the top three or four, a dogged man who can draw lines between dots that other people can't even see. Lately, he has become the man who breathes life into cold cases.

Through Schembri's work, authorities have made arrests in three major murder cases, the kind that keep detectives up at night chewing on antacid. The men who police think killed Jeanine Harms, Gretchen Burford and Beyerly are behind bars.

``He's one of the best detectives I've ever seen,'' says Tom Wheatley, former acting San Jose police chief. ``If I had the heaviest kind of case, he's one of the less-than-a-handful of guys I've met that I would assign it to. He does things that are just intuitive.''

Vintage Schembri: Nearly two decades ago, when he worked sexual assault cases for San Jose police, where he spent 28 years, Schembri noticed a colleague was bogged down on a vicious rape case.

``He's working it from the seat of his pants,'' Schembri said, describing his desk-bound colleague. ``So I say, let's go get a car, we can arrest him, there's some leads here.''

It was partly a sally in the dark. Schembri had no suspect. The assailant, however, left a Camel cigarette at the crime scene. The police knew he had called the victim from an East Side shopping center. The victim described a rapist with a bad case of eczema.

The detectives started at the shopping center, asking store managers if they remembered a weird guy with eczema who bought Camels. Bingo. A clerk remembered seeing a transient who fit that description and thought maybe he worked at a carnival.

That led them to a camper in the back of the shopping center, where a woman answered their knock. The cops asked her whether she lived with anyone. She mentioned her son. Could they talk to him? Well, OK. Still wearing the victim's T-shirt, the sleeping son had a bad case of eczema. He also was a suspect in a killing in Washington state.

``When I get a case, particularly if it's a rape, I usually go to the scene at the time of day the crime happened, just to get the feel of what happened,'' Schembri explains. ``You can never tell.''

Schembri has had plenty of backing in his quest to find out what happened in the baffling cases. The county has a good crime lab that has helped him quantify such evidence as rug fibers or DNA patterns. District Attorney George Kennedy and Chief Assistant Karyn Sinunu have assigned a veteran prosecutor, Charles Constantinides, to handle cold cases.

To this mix, Schembri, a bicyclist in the police Olympics, brings two uncommon ingredients. One is an innate ability to read people, to sense when a suspect is lying. When he flew to a Texas prison to interview Tyrone Hamel, the accused killer of Burford, a Palo Alto lawyer who was stabbed to death in 1988, Schembri never got a confession. But he did get an occasional smile to a direct question. At the end, he coaxed Hamel into saying that he felt sorry for Burford's family.

The second ingredient Schembri brings is that he's not afraid to fail. ``If you get a tough case, some people might say, `I don't know if this guy did it or not.' I always say, `What do I have to lose by taking this on, to get to the bottom of it?' You could be the victim here.''

On cold cases, this approach sometimes places Schembri in a delicate political posture. Not all police departments welcome help from the district attorney.

Mistakes of others

In the Beyerly case, Schembri does not disguise his low opinion of the 1978 Los Altos police investigators. He says they failed to do the job right, assuming Beyerly was a runaway because she had run away before.

Schembri started at a different point. He knew Beyerly's mother had seen the 17-year-old Los Altos High student crying because she had broken up with Schultz on the telephone. Beyerly felt she owed it to him to do it in person. Her life was turning around. She had a new boyfriend and had a hair appointment planned. To Schembri, that didn't feel like a runaway.

The investigator went to where her bones were found in 1979, the steep China Grade in the Santa Cruz Mountains. It wasn't a place where a casual killer would dump a body. It demanded that the killer have four-wheel drive and know his way around the mountains.

That led him to questions about China Grade. Whom could he tie to the area? Finally, one of his witnesses told him something she hadn't revealed in 1979: Schultz's uncle lived nearby. Schultz visited him frequently.

That made one of the original errors in the case more poignant. Schembri says a private investigator for the family took mud samples from the wheels of Schultz's vehicle a few days after Beyerly disappeared. The investigator turned over the mud to the Los Altos police, who -- alas -- did not preserve it. (Los Altos Police Chief Bob Lacey, who joined the department in 1980, said he had not heard that story.)

Broken patterns

A last true story: Patterns help detectives. People often repeat where they go, what they do. In the case of Harms, a 42-year-old Los Gatos woman who disappeared after going to a bar, investigators began focusing on architect Maurice X. Nasmeh, one of two men seen with her that night. Always interested in the personality of a suspect, Schembri asked about his patterns: How did he treat other women he dated?

Schembri says Nasmeh would usually call the woman the next morning to thank her for the date. He left no message for Harms. It's hardly enough to convict anyone. To a detective like Schembri, though, it was telling. You wouldn't thank someone who was already dead.