When the name Kathleen McCluskey kept cropping up in connection with drug deaths in Cambridge, police decided she was either a very unlucky woman or a very evil one.
Operation Falstaff was launched in September 2001 because of McCluskey's "proximity" to the deaths of four men who all died of drug overdoses.
The deaths took place in the sordid milieu of Cambridge's chronic drug addicts.
The genteel university city has a squalid underbelly inhabited by scores of heroin addicts.
Police estimate that burglaries by addicts trying to pay for their habit cost up to £1m a year in Cambridge.
James McCluskey, 44, was her second husband. They married in September 2001, eight months after her first husband committed suicide using a vacuum cleaner pipe attached to his car's exhaust pipe.
Two others, who survived, gave police statements which cast further doubt on her assertions of innocence.
Detective Chief Inspector Paul Craig decided to arrest McCluskey and charged her with administering a noxious substance to Charles Horsepool, who had survived an overdose in June 2001.
In January 2002 McCluskey was transferred from prison to Rampton Hospital in Nottinghamshire because of concerns over her mental state.
She was assessed by doctors who eventually decided she was fit to stand trial.
But Cambridgeshire Police officers have admitted they were surprised the case got as far as a trial because of the difficulty of proving McCluskey's intent to kill.
They were also painfully aware there was no motive - financial or otherwise - for her to kill any of them.
Mr Assadi died of a heroin and alcohol overdose
Kathleen McCluskey's life was nothing if not unorthodox.
Born in Yorkshire as Kathleen Baxter, she ran away at the age of 16 and lived in Brighton and London before eventually turning up in Cambridge.
In 1994 she married James Wormold and he took her surname as his married name.
But theirs was an open marriage and they attended sex and drugs parties in Cambridge together.
On 20 August 1999 they attended a party at Mr Assadi's house.
Mr Baxter eventually left but his wife remained and in the early hours of the following day she rang an ambulance and paramedics arrived and pronounced Mr Assadi dead.
In March 2000 a coroner recorded an open verdict on Mr Assadi.
Three months later Kathleen Baxter had sex with Marvin Brodie and the following morning took a taxi back to her home with him so she could take her methadone.
Later that day Brodie was found dead and once again paramedics were called by Mrs Baxter and they found him with an empty bottle of methadone beside him.
She was acquitted of killing James McCluskey
Again an open verdict was recorded at an inquest.
James Baxter committed suicide in January 2001 and his widow was free to set up home with James McCluskey who she soon married.
Ray Diaz, another addict, lived nearby and visited the couple regularly.
On 29 March 2001 Diaz bought some heroin but it was "no good" so he went to the McCluskeys to get something better.
An hour later he collapsed and a post mortem later attributed the death to an alcohol and heroin overdose.
On 25 September 2001 James McCluskey bought some heroin and was found unconscious early the following morning.
He died of alcohol and methadone poisoning.
Ray Diaz died of an overdose
A month later Mr Horsepool made his complaint - he had fallen ill in the summer of 2001 after taking a vodka and herb concoction made up by Kathleen McCluskey, with whom he was having a sexual relationship.
In November 2001 Peter Bakulinskjy came forward to report an incident which had happened on Christmas Day 1999.
He had drunk methadone with an unknown additive at Mrs McCluskey's home and was unconscious for five hours.
McCluskey was later acquitted of administering a toxic substance - methadone - to him.
But sentencing McCluskey on Wednesday Mr Justice Moses said that in the case of Mr Assadi and Mr Brodie the jury was sure the drug was not taken in the exercise of a fully voluntary choice.