An international police hunt has been launched to find the missing lover of a woman who murdered her husband.

Bigamist Dena Thompson, nicknamed the Black Widow, was jailed for life in 2003 for murdering her second husband Julian Webb at the home they shared in Yapton, near Arundel.

After her conviction Sussex Police tried to trace all of Thompson's former lovers, amid fears they had stumbled across a serial killer.

However a Bulgarian man she dated in the 1970s and 1980s was never found.

Interpol is now believed to have resumed the search for her former boyfriend Stoyan Kostov.

Investigators in Bulgaria have also been trying to trace Mr Kostov who has not been seen in 30 years.

Mr Kostov, apparently disappeared while he was dating Thompson, then known by her maiden name Holmes, who was training as a gymnast Svishtov, Bulgaria.

Investigators behind the latest probe said that: “Some sort of incident seems to have happened in Bulgaria but we don’t know what it was.”

After Thompson's murder conviction, investigating officer Detective Chief Inspector Martyn Underhill said: “We cannot rule out the possibility that other partners have been injured in some way.’ “This woman is every man's nightmare. For a decade she has targeted men sexually, financially and physically.

“Stoyan Kostov 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.”

Thompson killed her second husband Mr Webb for his £36,000 life insurance, using the spicy curry flavour to disguise anti-depressants and aspirin she had hidden in his dinner.

Judge Michael Hyam who presided over Thompson's 2003 trial at the Old Bailey described her as “utterly ruthless and without any pity”.

Her crime was only discovered when Mr Webb's body was exhumed after she was acquitted of trying kill her third husband, Richard Thompson, from Littlehampton.

She was accused of trying to use a baseball bat and carving knife to kill him during a bondage sex session.

Thompson was however jailed for three years and a half years for 15 counts of deception involving thousands of pounds that she stole from Mr Thompson and two other lovers.

No one from Interpol was available for comment on their investigation yesterday.