If there was ever a woman with reason to live, it was Sue Snow. Although she had dropped out of high school after an early marriage, she had risen by virtue of hard work to an assistant vice-presidency at a branch of the Puget Sound National Bank, south of Seattle. At 40, she was the mother of two daughters, one grown, one a teenager, but she still had her cheerleader good looks. Twice divorced, she was newly remarried and so entranced with her husband, truck driver Paul Webking, 45, that they were rarely apart. "We were madly in love," he said later.

On June 11, 1986, the love story ended abruptly. Rising at 6, Sue Snow took two Extra-Strength Excedrin capsules, as was her morning habit; she counted on the caffeine in it to give her a little lift.

Fifteen minutes later, her daughter Hayley, then 15 years old, found Sue Snow sprawled unconscious on the bathroom floor. By noon she was dead. A few days later, the King County medical examiner announced that she had been poisoned; her Excedrin had been laced with cyanide. Snow's grieving family was bewildered. They knew of no one who might have wanted her dead, and they could imagine no motive for the crime. Nearly two years would pass before a suspect was brought to trial and her family realized that Snow had been precisely the victim the killer had sought: a perfect stranger.

In September 1982, seven people in Chicago died within 18 hours of taking cyanide-contaminated Extra-Strength Tylenol. The crimes were never solved, and the country was left with a terrifying question: What sort of person was it who would play assassin in such a mindless, random fashion? Sue Snow's death, in the city of Auburn, Wash., suggested that a copycat killer seemed to be on the loose. Within a week a second victim had been identified.

Yet this case would be different; for the first time, police would solve a product-tampering death. In December 1987, they made an arrest, and finally, two weeks ago, Stella Nickell, 44, of Auburn, was sentenced to 90 years in prison for the crime. Her story turned out not to be that of a madwoman but of a coldly calculating killer who knew what she was doing and why.

Forty is a dangerous age, whether you live in a mansion or, as Stella Nickell did, in a trailer park. Old dreams are measured against reality. Reality, generally speaking, comes up flat. So it was, at any rate, for Stella Nickell.

Here she was, said to be fond of bar-hopping and, judging by her courtroom attire, skintight dresses. She had married Bruce Nickell, a hard-drinking heavy-equipment operator, only to have him take stock and dry himself out. Here was Stella, dreaming of cash she didn't have. According to the prosecution, Stella figured that if she had the money, she could own the piece of property her trailer was sitting on and she could open a tropical fish store. She had always been partial to fish.

Stella's life, up to that point, had not been the stuff of dreams. Born in a small town outside Portland, Ore., she had grown up poor, gotten married and had her first daughter, Cynthia, at 16. Later, in Southern California, there was another daughter, and some run-ins with the law. In 1968 she was convicted of fraud and in 1969 the felonious beating of Cynthia; in 1971 she was convicted of forgery.

Now, 10 years into her second marriage, she was living in Washington State. Her life was more settled, but it was grim. Her elderly mother was living next door. Cynthia, who'd grown up to be a beautiful redhead, was divorced and temporarily raising her child in Stella's trailer. Money was always a problem. Bruce, 52, was out of work more often than not and, Cynthia reported, had been getting on Stella's nerves. For five years, Cynthia says, her mother had been talking about solving her problems by killing her husband.

Cynthia testified that her mother set out to arrange an accident. She studied library books on poison and administered a dose of toxic seeds, either foxglove or hemlock, to Bruce. His only notable reaction was lethargy. Having attended a rehabilitation program with Bruce, where she learned that recovering alcoholics are susceptible to other addictive substances, Stella toyed with the idea of killing him with heroin, cocaine or speed, so that the death would look to police like just another accidental overdose.

Then in the spring of 1986, according to Cynthia, Stella's thoughts turned to the Chicago Tylenol poisonings. They intrigued her, she told Cynthia. Why couldn't Bruce be done in like that? "I knew she was capable of it," a tearful Cynthia told the court. "But when it's your own mother, you don't want to believe she could."

Stella's actions soon indicated that she could and would. In the fall of 1985, she took out $40,000 in insurance on Bruce's life, naming herself as sole beneficiary. Bruce also held a state employee's policy for $31,000, which promised an additional $105,000 in the event of accidental death.

On June 5, Stella testified, Bruce Nickell came home from work. He kissed her, then, since he had a headache, went into the kitchen and reached for a bottle of Excedrin. Some capsules in the bottle were untainted, others contained more than three times the lethal adult dose of cyanide. Stella testified that she saw her husband swallow four pills. He watched TV for a while, then took a stroll on the patio.

Suddenly, Bruce Nickell called out from the patio.

"Babe?"

"What do you want?" asked Stella.

"I feel like I'm going to pass out."

At that point Bruce collapsed, unable to speak. Stella Nickell called a paramedic, and her husband was helicoptered to Harborview Medical Center in Seattle. Stella declined to go to his bedside, testifying later that she was too upset. Bruce never regained consciousness, and within hours he was dead. The next day, when Stella told Cynthia her "daddy" was dead, she felt obliged to issue a disclaimer: "I know what you're thinking, and the answer is 'no.' "

Stella hardly intended to fall under suspicion, but it was essential that Bruce's "accidental death" be established. The coroner's report must have been a major disappointment. Failing to detect the cyanide in Bruce's body, doctors concluded that he had died of pulmonary emphysema. Stella stood to collect $71,000 in insurance money, but that was $105,000 less than she had expected. As the prosecution saw it, she had no intention of settling cheap.

There was only one way she could show that her husband had died as a result of an accident, the prosecution argued: Someone else—it didn't matter who—would have to die to alert King County authorities that a random cyanide killer had struck.

At some point, Stella opened a number of containers of Extra-Strength Excedrin and Anacin-3, emptied some of the capsules and refilled them with cyanide. The results were not the work of an artist; seals on the containers were cut or missing, the boxes amateurishly reglued. Somehow, said the prosecution, Stella managed to slip the tainted packages onto the shelves of three stores. Sue Snow, who lived 12 miles away, bought one of those packages.

Six days after Bruce Nickell's death, Paul Webking, Sue Snow's husband, got ready to go to work, grabbed two Extra-Strength Excedrin capsules for his arthritis and kissed his sleepy wife goodbye. "I always told her I loved her," he said later, "and she told me she loved me." When he saw her next, six hours later, she was on a respirator in the hospital, brain dead. By the luck of the draw, his Excedrin capsules had not been poisoned.

The King County medical examiner announced three days later that Snow had died after taking tainted Excedrin capsules. Within a week, Stella stepped forward, hesitantly suggesting that her husband, who had also taken Excedrin shortly before becoming ill, might have been a victim of the same sort of poisoning. New tissue tests proved Stella right. Almost at once, nonprescription capsule medications were ordered removed from store shelves all over the county. Paul Webking filed a wrongful death suit against the Excedrin manufacturers, Bristol-Myers. Stella Nickell filed one too.

As in most drug-tampering cases, the investigation was difficult, but Stella Nickell gradually became a strong suspect. Authorities found it especially curious that two of only five contaminated bottles of painkillers recovered in the area were found in her home. Detectives soon learned of the insurance policies on Bruce's life (Stella's claims have not been paid), and Stella failed a lie-detector test. Even so, the 85 FBI agents and police officers on the case did not have the evidence to bring Stella in.

Then in January 1987 they got a break: Cynthia decided to talk. She said she was coming forward because it was "the right thing for me to do." Her mother's attorney suggested that Cynthia was inspired rather by a $300,000 reward offered by over-the-counter drug manufacturers, which she has yet to receive.

In April, Stella Nickell went to trial in federal court in Seattle, where assistant U.S. attorney Joanne Maida described her as "an icy human being...without conscience." The most damning testimony came from Cynthia, 28, whose carefully made-up face was streaked with tears as she told her story. She said her mother "was very pleased that [Bruce had] stopped drinking, but she didn't like it that they didn't do anything anymore."

In May a jury convicted Stella Nickell of causing death by product tampering; she was the first person brought to trial and the first convicted under a federal law enacted in 1983. On June 17, smiling broadly, she was brought before Judge William Dwyer for sentencing. Her lawyer asked for mercy, arguing for "a sentence that would allow some hope." But the judge, citing crimes "of exceptional callousness and cruelty," was of another mind, imposing the 90-year sentence, which makes her ineligible for parole until 2018, when she will be 74 years old.

There was no response from the defendant. She managed a smile as she was taken away. The daughter she had abused in childhood—and then burdened with suspicion of her terrible crimes—was not present to see her depart.

—By Joyce Wadler, with Meg Grant in Seattle