Stella Nickell is convicted of murder after she put cyanide in Excedrin capsules, a painkiller. She killed her husband after he took a capsule for a headache.

Her devious plan was apparently born after, when she killed her husband with the cyanide, doctors misdiagnosed his death as emphysema.

She had taken out a $100,000 accidental death policy on his life a year before and she needed an accident for the policy to pay out.

So Nickell tampered with four other bottles of Excedrin and put them on store shelves.

Susan Snow died instantly after taking one of the tampered pills. When her death was reported on the news, Nickell called police to tell them she thought her husband had also been poisoned.

So far her plan was working out and she would probably have gotten away with it, however...

When police came to her house to collect the Excedrin bottle her husband had used, she told them she had two bottles, bought on two different days, from different stores. Both contained cyanide. This was highly unlikely.

Nickell's fate was sealed when her daughter came forward to tell them of her mother's plans to kill her father. The daughter gave evidence that her mother had spent time in the library researching cyanide. Nickell even had a library book out which she had never returned, it was called 'Human Poisoning'.

Nickell got 90 years, possible parole in 2018.