A French murder trial that opened Monday has transfixed the public because of the mystery at its core: where is the victim's body?

Cédric Jubillar, a 38 year-old painter-decorator, is accused of killing his wife Delphine nearly five years ago in a fit of jealous rage.

He has always denied the charges and, other than circumstantial evidence, investigators have struggled to build a case. There is no body, no blood, no confession, and no witness.

With its unexplained central fact and its cast of characters from small-town southern France, the affair has become a social media sensation.

Self-declared investigators have set up countless chat groups where they swap theories and share testimony – much to the irritation of police and families.

These groups are the equivalent of the bistro counter – but with more people, said psychoanalyst Patrick Avrane, author of a book on attitudes to crime.

Everyone constructs the theory that suits him or her the best.

The Jubillar mystery began at the height of Covid lockdown when – in the early hours on 16 December 2020 – Cédric Jubillar contacted the gendarmes to report that his wife had gone missing.

Delphine, who was 33 at the time, was a night nurse in a clinic not far from their home in Cagnac-les-Mines in the south-western Occitania region. The couple had two children, aged six and 18 months.

Police came to understand that the Jubillars did not have a happy relationship.

Cédric Jubillar was a habitual cannabis user and barely held down a job. Delphine was in a relationship with a man she had met over the Internet. She and Cédric were talking about divorce.

Police and locals conducted extensive searches in the surrounding countryside – with potholers descending into some of the disused mineshafts with which the area is dotted.

Delphine's body was never found, but a case was gradually built against her husband and in mid-2021 he was placed under investigation and detained.

The prosecution at the trial in the town of Albi will assert that Cédric Jubillar had a clear motive for killing his wife, primarily due to their impending separation.

Lawyers will highlight certain peculiar actions by Cédric on the night of the disappearance, signs of a struggle – including a pair of broken glasses – and a neighbor who heard a woman's screams.

Cédric Jubillar's character will also be scrutinized, with witnesses expected to testify about his threatening behavior towards Delphine before she went missing, as well as his apparent indifference thereafter.

Two acquaintances, a former cellmate and an ex-girlfriend, have indicated that Cédric confessed to them about the murder and purportedly revealed where her body was hidden.

However, no body has been discovered despite extensive searching, leading the defense to challenge the credibility of these claims.

At the heart of Cédric Jubillar's defense is the argument that there is insufficient evidence – apart from popular opinion labeling him the likely culprit – to substantiate the accusation of his wife's murder. He has consistently maintained his innocence.

The trial is expected to last for four weeks, comprise 65 witnesses, and feature 11 experts, with over 16,000 pages of evidence reviewed.

Reflecting on the public's fascination, writer Thibault de Montaigu noted in Le Figaro that the case resembles a story by Georges Simenon, the creator of the fictional detective Inspector Maigret.

In a detailed analysis, he pondered how a man described as a red-eyed, fuzzy-brained guy who smoked ten joints a day could have orchestrated the perfect crime.

Killing his wife without leaving the slightest trace; secretly transporting her body, burying her in an unfindable location, then coming back to tell the police – all while his two children slept quietly in their bedrooms.

So: genius bluffer; lucky fool; or poor innocent?

The court will ultimately decide.