A bigamist dubbed the Black Widow has been jailed for life for murdering her second husband on his 31st birthday.

Three-times-married Dena Thompson, 43, poisoned advertising manager Julian Webb with a lethal cocktail of anti-depressant capsules, possibly hidden in his favourite meal - a hot, spicy curry.

A jury at the Old Bailey convicted her of killing Mr Webb at the home they shared in Douglas Close, Yapton, near Arundel, in June 1994.

And after the verdict, detectives revealed that they are trying to trace a previous boyfriend of the killer.

Detective Chief Inspector Martyn Underhill said a Bulgarian man disappeared following a relationship with Thompson.

He said: "Stoin Costov had a relationship with her for quite a while in the Seventies and they travelled between Bulgaria and the UK.

"We cannot trace him. We have tried in this country and through Interpol to find him. We are calling on him to get in touch."

Mr Webb was buried in Hayling Island, Hampshire, and an inquest into Mr Webb's death recorded an open verdict.

However, the truth emerged seven years later when his body was exhumed after Thompson was cleared of trying to kill third husband Richard Thompson.

Yesterday the jury of six men and five women took ten hours and 23 minutes to announce a guilty verdict by a 10-1 majority following a five-week trial.

Members of Julian Webb's family, including his mother Rosemary Webb, a teacher, and cousin Nick Ive embraced as it was delivered.

Outside court, Mrs Webb, from Hayling Island, gathered her family round her and spoke of her relief that justice had been done.

She said: "Julian was a much-loved, kind, loyal and friendly young man. He is greatly missed by his family and friends and their support has been a great help to me.

"The circumstances surrounding his death have been the source of great pain to me and my family. Even now only one person knows what really happened and she is not saying.

"I would like to thank the police and legal teams who have been involved with me and cannot thank them enough. They have kept me informed throughout and have always treated me with kindness and support.

"I cannot emphasise too highly how impressed I have been with their efforts in the investigation and prosecution of the evidence.

"Those of us who knew Julian well know he would never have committed suicide. He had a close circle of friends, lots of interests and activities.

"He was a happy, straight-forward personality. He thought a great deal of his step-son and hoped one day he would have a child of his own.

"He was a trusting person and he often expressed concern for the problems Dena seemed to be having. He was glad he was there to support her.

"It is with great sadness those of us who are here have discovered what she is really like. She is dishonest, untruthful, manipulative, deceitful and scheming.

"We miss him. There is never a day when he is not the first thought I have when I awake."

The jury was not told before their verdict Thompson, of Larks Rise, Cullompton, Devon, was acquitted three years ago of attempted murder after a jury at Lewes Crown Court heard she attacked Mr Thompson with a baseball bat and knife because she feared for her life during a bondage sex session.

But she was convicted and jailed for three years and nine months for conning Mr Thompson and two former lovers out of £12,000.

Mr Webb's body was dug up the following year when police found a witness who said Thompson told him about the curry.

New tests showed higher levels of drugs in his body than had first been thought and evidence which could be interpreted to show slow poisoning over a number of days.

Outside court, Detective Chief Inspector Martyn Underhill said: "Dena Thompson is the most dangerous woman I have ever met. She is every man's nightmare.

"The men of southern England can sleep safe tonight knowing she has been taken off the streets."

Friends described Mr Webb as a "happy-go-lucky" man who never let problems get on top of him.

However, during the last week of his life his routine changed. He did not go to work and stopped going to the gym.

Michael Birnbaum QC, prosecuting, said Thompson prevented friends and relatives from speaking to her husband.

The defendant told police after the murder how Mr Webb had become depressed after being refused a permit to work in America.

Thompson maintained he had "hit the bottle" in the days up to his death.

It was discovered after Mr Webb's death Thompson had phoned his friend Don Hutson in America and told him her husband had become ill after eating a curry on his birthday.

Mr Birnbaum told the court: "Dothiepin is a drug with a bitter taste and it would be hard to administer it to someone else unless it was disguised.

"She may have disguised it with spicy food such as curry. This was death by trickery."

Mr Birnbaum said Thompson was a "disturbed person" leading a double life which was threatening to catch up with her.

She had married first husband Lee Wyatt in 1984 and secretly kept in touch with him after a romance and bigamous marriage to Mr Webb in 1991.

During her marriage to Mr Webb, she stole almost £24,000 from the Woolwich Building Society in Arundel, where she worked.

The court heard she tried to frame Mr Wyatt, 48, but she was convicted in 1995 and sentenced to 18 months in prison.

Mr Wyatt said he spent years on the run, believing Thompson's lies the family were in danger from the Mafia.

Thompson filed for divorce two weeks after Mr Wyatt applied to buy the house in Yapton in 1991. The sale went through but the divorce was not finalised until 1997.

Mr Wyatt said he had produced a soft toy called Sean the Leprechaun and believed Thompson when she told him they had been offered up to £50 million for the rights.

She told him the Mafia had threatened to kill her son Darren unless they got their share - and Mr Wyatt had to disappear while a new life was being arranged for them in America by Walt Disney.

Mr Wyatt changed his name while keeping in touch with Thompson by phone.

The jury heard Thompson began to fear Mr Wyatt would meet Mr Webb and murdered her new husband so her double life as a fraudster and bigamist would not be exposed.

Sentencing Thompson to life, Recorder of London Michael Hyam said: "What you did was utterly ruthless and without pity."

Thompson's solicitor Steve Wedd said: "She is devastated that she has been convicted.

"She believes she has been convicted because of who she is, not what she did."