Police investigating the 1986 deaths of Sue Snow and Bruce Nickell zeroed in on Stella Nickell, Bruceís widow as a suspect in both crimes. Nickell had a motive, the opportunity, and most damning of all, she had not one but two poisoned bottles of Extra Strength Excedrin in her home.
After a nationwide recall of the medication, authorities found only two more tainted bottles, both in Washington State. The odds that Nickell would possess two of only five poisoned bottles seemed astronomical. Further, all the tainted capsules contained green flecks mixed in with the cyanide-flecks which were determined to be the same type of algae killer used by Nickell in treating her fish tank. Adding to police suspicion was Nickellís failure of a polygraph test.
In January 1987, Nickellís daughter Cindy Hamilton informed police that Nickell had been speaking of killing Bruce for quite some time before his death. Nickell, Hamilton said, had grown tired of Bruce and wanted out of the marriage. She told authorities that Nickell had researched various poisons, including foxglove and cyanide, at the library before carrying out the murder.
Police examined Nickellís library records and found that she had in fact checked out books on poison. They were able to lift her fingerprints from one book, with the most prints found in the part of the book that discussed cyanide. Based on Hamiltonís story and the evidence they had gathered against Nickell, police arrested her and charged her with two counts of murder.
During Nickellís trial, State witnesses included her daughter and handwriting experts that testified that Bruceís signature on the life insurance policies Nickell took out on him were forged. It was these very life insurance policies, the prosecution argued, that put not only Bruce, but Snow as well, in their graves. The State theorized that Bruceís life insurance policies were not set to pay as much as Nickell had expected, because his death was ruled as natural causes. In order to collect the full amounts, Nickell had to convince authorities her husbandís death was due to poisoning, without drawing their suspicion. The prosecution stated that Nickell then hatched the plan to poison three other bottles of Extra Strength Excedrin and replace them on store shelves, not caring who purchased them. When the story of the poisoning broke, she could then come to police and question whether Bruce was also a victim of the unknown serial poisoner.
Despite defense objections that Hamilton was lying, motivated only by a $250,000 reward from the drug companies, the jury found Nickell guilty of murder in 1988. She was the first person tried under anti-tampering laws brought about by the 1982 Tylenol poisonings in Chicago, which prescribed harsher sentences for offenses related to product tampering. Nickell was sentenced to 90 years in prison, with no eligibility for parole until 2017.
In recent years, private investigators Al Farr and Paul Ciolino have become convinced of Nickellís innocence and have worked with her defense team to overturn her 1988 conviction. They cite false testimony from Hamilton, witness tampering and withheld evidence as their reasons for believing Nickell is innocent. As of May 2011, attempts to gain a new trial have been unsuccessful.