Shana and Kevin, aged 18 and 22, were found dead in a burning car barely half an hour after leaving a family party on New Year’s Eve. Both had been shot in what was described as a professional manner. Janssen, who lived next door to the Appeltans family, was interviewed the following Tuesday, at which point the Hasselt prosecutor would only say there were “indications but not proof” of his involvement.

By the following day, investigators said they had found “clues” during a search of Janssen’s home – firearms (but not yet the murder weapon), and he was officially placed under arrest as a suspect.

Janssen, 38, is divorced and the father of two daughters, aged eight and 11. He teaches technical drawing at a school in Herk-de-Stad, where Shana had once been a student. Reports said he enjoys a spotless reputation at the school, while neighbours were divided between finding nothing to remark upon and considering him somewhat solitary and distant.

According to reports, attributed to unnamed sources “close to the investigation”, there had been a longrunning feud between Janssen and Paulus, which came to a head on New Year’s Eve and led to the shootings. Janssen alone killed both victims and set the car on fire to destroy evidence, he confessed.

By Wednesday, 6 January, speculation emerged that Janssen might be able to provide a lead in the case of the murder of Annick Van Uytsel, fuelled in part by star lawyer Jef Vermassen, who represents Annick’s family. According to Vermassen, his knowledge of the Van Uytsel investigation, together with his familiarity with serial killer cases, led him to believe Janssen might be involved.

At a packed press conference last Monday morning, the Leuven prosecutor announced that Janssen had indeed confessed to Annick’s murder. It was made clear there would be no more information released on the matter.

Details of Annick’s murder – not least a motive for the killing – are far from being clear. Annick’s body was wrapped carefully in plastic sacks and dumped in the Albert canal, and investigators found no trace of the killer’s DNA. How and why she was killed, and whether there are more revelations to come from Belgium’s latest serial killer, will for now remain a mystery.

It has emerged that Janssen was already linked to the Annick Van Uytsel case by an anonymous tipster, who had contacted police investigating the murder. The tip was said to be “too vague” to be of any use. “We certainly didn’t do anything wrong,” a spokesman for the Leuven prosecutor said.