Michel Fourniret, whose victims were mostly girls and young women, died at the La Pitie-Salpetriere hospital in Paris where he was admitted on April 28th from the nearby Fresnes prison.

An investigation has been opened into his death, Heitz said, which is normal procedure in France when a prisoner dies.

Le Parisien newspaper reported Monday morning that he was taken to hospital suffering from a heart condition and Alzheimer’s, and that doctors had placed him in an artificial coma.

Fourniret had collapsed in his prison cell on November 20th, only two weeks before police were to start digging for the remains of nine-year-old Estelle Mouzin, who he had recently confessed to killing.

A bespectacled, chess-playing lover of literature who lived in a sprawling chateau, for 15 years Fourniret roamed eastern France looking for virgins to rape and kill, using his wife to lure young girls to their deaths.

By the time he was arrested in 2003, the “Ogre of the Ardennes” was one of Europe’s most notorious serial killers.

Fourniret confessed to 11 murders – including of British student Joanna Parrish – but has been linked to other disappearances.

His youngest victim was Estelle Mouzin, a nine-year-old girl who he raped and killed months before he was caught in Belgium trying to kidnap a 13-year-old.

But it was the sordid pact between Fourniret and his third wife, Monique Olivier, that sparked still greater revulsion.

She agreed to help him find virgins to rape if he killed her husband.

The pair married while Fourniret was still serving his second jail sentence for sexually assaulting young girls.

While in prison he shared a cell with a bank robber from one of France’s most infamous gangs.

After his release, the robber’s wife asked Fourniret to dig up stolen gold buried in a graveyard.

But the couple strangled the woman, and used the loot to buy a chateau.

Fourniret later admitted gong ‘hunting’ for a virgin to kill at least twice a year. And the chateau’s extensive grounds became a burial ground for at least two of his victims.

Fourniret was born on April 4th, 1942 in Sedan near the Belgian border in northeastern France.

Little is known of his childhood but he served in the French army during the brutal war of independence in Algeria, which was then part of France.

He later worked as a carpenter, electrician and even a supervisor in a school.

His sexual crimes began soon after his return to France, when as a 25-year-old he was given an eight-month suspended sentence for attacking a girl in his native Ardennes region.

His first wife divorced him soon after but he carried on committing sex crimes until 1984, when he was jailed again for attacking a young woman.

After his second wife left him he placed an ad in a newspaper looking for a pen pal and Olivier replied.

She was waiting for him outside a prison near Paris when he was released in October 1987.

Their first joint attack, barely two months later, set the tone for the others.

The couple drove up alongside 17-year-old Isabelle Laville and asked her for directions, persuading her to get into their van and show them the way. She was never seen again.

Olivier’s presence, sometimes with their baby son, was aimed at allaying suspicion.

When a girl they kidnapped escaped from his clutches in 2003 Olivier confessed to Belgian police. Fourniret never did kill her ex-husband.

Prosecutors said that she was “very much under his spell”.

But afraid she could get a heavy prison sentence like the one given to the wife of the Belgian serial killer Marc Dutroux, she spilled the beans.

The pair were tried in France in 2008, with Fourniret sentenced for life for the murders of all seven of the victims whose bodies had then been found.

Olivier, who is now 72, also got life with no possibility of parole for her complicity.

After close to 13 years behind bars, and in poor health, Fourniret confessed to killing Parish in 2016 and to two more murders two years later.

Last year the couple – who have divorced – admitted to killing and raping nine-year-old Estelle Mouzin on her way home from school near Paris a few months before their arrest in 2003.

Fourniret’s death crushed the hopes of those hoping to see him put on trial over the disappearances of Estelle Mouzin, Parrish and two other women suspected of being among his victims.