Enigmatic to the end, the gunman called Silas Cool has taken any clear explanation of last year’s Metro bus shootings to the grave with him. Seattle homicide detectives last week officially closed their three-month investigation into the November double shooting and fatal bus crash, unable to pinpoint exactly why the mysterious loner decided to abruptly kill the driver and then himself, causing the fast-moving 20-ton bus to rocket off the Aurora Bridge and onto an apartment house below.

But police did in the end assemble a raggedy portrait of the tall, lean, steely-eyed petty thief, Peeping Tom, and onetime Boy Scout who favored sunglasses at night, slept on an inflatable mattress, obsessively collected ointments, ate dinner at street missions, and lived off free money from his parents and $30,000 in certificates of deposit. In retrospect, the police file indicates, the ever-eccentric Steven Gary Cool, a.k.a. Silas Garfield Cool, 43, had become increasingly angry and unpredictable in the final few months of his life and was plotting a bus shooting. Suffering from both severe chronic back pain and outward signs of paranoia, the gun-packing Cool so feared and disliked other bus passengers and Metro-King County bus drivers that a single gun no longer fit his need. In October, he quietly showed a handgun to a passenger and said he was getting a second gun so he could deal with the “mean” people who ride and drive buses.

That was the exact feat he accomplished Friday afternoon, November 27, 1998. Armed with two guns—one of them the weapon he had displayed a month earlier—Cool undertook the assassination-style shooting of Metro bus driver Mark McLaughlin, 44, that led to the spectacular bridge crash, injuring 32 passengers, disabling some of them permanently, and killing one, 69-year-old Herman Liebelt.

However, the police probe also determined that Cool’s apparent attempt to take a near-busload of passengers to their deaths may have been thwarted by the last-second heroics of the very man he killed. Shot twice point-blank with a .380 caliber semi-automatic pistol, the dying McLaughlin managed to still apply the brakes just before bus no. 2106 sailed off the bridge. The slower speed lessened the bus’s impact and possibly saved many lives.

Accident investigators re-creating the scene determined the 60-foot articulated bus was doing almost 50 miles an hour on the bridge when Cool jumped up and shot McLaughlin in the chest and lower right side, one of the bullets entering and passing through his right arm. The bus swung out of its southbound lane and drifted for 100 feet across the northbound traffic, glancing off a van and heading for the concrete bridge rail. But in the final 40 feet, with the front of the bus going almost directly east on the six-lane north-south bridge, McLaughlin—presumably slumping over the wheel with two slugs in him—somehow operated the brakes. Cool in those final seconds was already dying or busy killing himself, holding a gun to his head and firing a bullet clean through it.

Detective Ron Sanders reports there was “evidence of braking” in the final seconds, which brought the bus’s speed down from 49 mph to 40 mph.

McLaughlin “kept the bus from going off farther along the bridge, over the water,” notes Metro spokesman Dan Williams. “It was pretty amazing.”

The dying McLaughlin, a 19-year veteran, was ejected through the windshield when his bus crashed and folded into a V atop the apartments. Quickly arriving medics were unable to revive him.

The police review completed last week puts to rest rumors of guns being carried by other passengers that day and squelches armchair theories that Cool didn’t act alone. “Silas Cool was the killer, that’s final,” says police spokesperson Carmen Best.

A copy of the report suggests Cool’s deadly finale may have been as unpredictable as his moods—to some he seemed quietly polite, to others suspicious, and to still others, scary, police found. But he was one very odd, frequently recurring blip on Metro’s radar. Within just a few days of the killings, transit drivers were calling detectives to recount Cool’s erratic behavior on their buses dating back at least three years. One recalled Cool had complained about heat on the bus, walking up and down the aisles opening windows and swearing at the driver. Others remembered him as the man with an intimidating stare, harassing, unruly, and obnoxious. One driver recalled Cool simply sitting and reading a newspaper with sun glasses on, but manifesting a “presence that scared her.”

A driver has also told reporters he thought Cool was the man who put a gun to the driver’s head in August, pulling the trigger twice—the gun was unloaded or misfired—and dashing off the coach.

A passenger told detectives Cool showed her a gun on a bus in October. Cool told her he had the gun because it was “a shame [the way] people behave on the bus and that it is also a shame that some drivers are so mean.” Detectives say Cool then “looked around the bus and said that he was going to get another gun.” Federal agents say Cool had bought both guns years earlier, one at a Green Lake gun shop.

Police also learned that Cool was considered “a weird fellow” 10 years earlier when he worked for what was then called the King County Building and Land Department. Employed there for four years, Cool, according to a supervisor, was anti-social and racist. The supervisor told police that “Cool quit the building department job, but was really forced out.”

Cool was born in Palembang, Sumatra, and brought up in wealth—his now-retired father in New Jersey was an oil-company accountant in Indonesia. After leaving King County’s employ, Cool’s parents supported him. At the time of his death, he received $650 a month from his parents and was given $30,000 in certificates of deposit by his aunt, police learned. He also may have lived at two residences at the same time: His parents told police they visited him at his rented apartment on east Queen Anne in 1991, but the landlord at his University District apartment says Cool had lived there since 1985, always paying his $475 rent on time.

Still, he apparently lacked the money he needed, dining sometimes at a downtown mission—where, he told an acquaintance, he had “undergone a religious experience”— and getting arrested twice for shoplifting. He was also arrested over the years for obstruction, false reporting, and, about two weeks before the bus shooting, for peeping into the women’s shower at a Mountlake Terrace recreation center.

His small, spare one-bedroom apartment included an empty refrigerator, mere sticks of furniture, piles of outdated bus schedules, tin foil on the windows, a wall of nude photos from girlie magazines, and in the bath an aging clutter of creams and ointments. One detective thought the sink looked long unused.

Cool’s father, Daniel, told police he thought his son was in great pain from the back condition. Silas/Steven had never been diagnosed with a mental illness, the father said, or even seen a counselor. He had once studied to become a civil engineer, but, Daniel Cool said, simply became a loner. He could not say why, exactly. “Cool and his wife,” Detective John Nordlund wrote in the police file now marked closed, “find it really hard to believe that Silas shot the bus driver. That would have been totally out of his character.”

Metro, which in the wake of the shootings added eight more King County deputies to its full-time transit security force, is expected to next week make a recommendation to add security cameras to some buses. “We think surveillance could go a long way toward identifying habitual-problem people like this and prosecuting them,” says Metro’s Williams. “And, maybe more important, toward deterring them.”