Image source, AFPImage caption, French reports said the man was a former member of France's military police force

For decades the crimes of a notorious serial killer have haunted the Paris crime squad.

But now a former military police officer is said to have confessed to being the man known as Le Grêlé – the pockmarked man – before he died.

In a suicide note, the man, named by French media as François V, said he was the killer whose crimes shocked Paris in the 1980s and 1990s.

The killer is suspected of being behind several murders and rapes.

DNA tests are yet to confirm that the man is Le Grêlé, but the dead suspect's confession could mark the end of one of France's most notorious uncracked cases.

The killer was given nickname in reference to his face, pockmarked by acne.

Among the infamous crimes attributed to him was the murder of 11-year-old Cécile Bloch. She was reported missing after failing to show up to school in the town of Fontainebleau in 1986.

Her body was later found in the basement of the apartment building she lived in, and the case sent shockwaves across France.

Cécile's half-brother passed a man in the elevator on the morning of the crime, and helped police to draw their sketch of the suspect.

DNA evidence linked her killer to other murders and rapes.

While the crimes date back decades, progress was made on the case only recently.

Reports say François V had been summoned for questioning in relation to the case and to give a DNA sample, but he did not show up.

His body was found on Wednesday at a seaside resort near the southern city of Montpellier.

While few details have been confirmed, Le Parisien newspaper reported that François V was a 59-year-old former gendarme – a policeman attached to the French military.

In his final message he said he was "not well in life" at the time of the killings, according to Le Parisien.

Cécile Bloch's half-brother has previously spoken about how the case has haunted him. "I manage to live, but I have a great feeling of injustice, irreparable," he told the Sud Ouest newspaper in 2015.