Paris - The brutal and what seems to be unprovoked murder of an 11-year-old boy in France has prompted investigators to suspect the work of a psychotic serial murderer over more than a decade.

Stephane Moitoiret was quickly identified and arrested as the possible killer by genetic material on the boy, called Valentin, who was found with 44 stab wounds near the city of Lyon on July 28.

Moitoiret, described as a vagrant with religious delusions, is now suspected of killing 20-year-old Marine Boisseranc three years ago, according to a report in Saturday's Parisien newspaper.

Marine's father Eric told the newspaper that the prosecutor in the Valentin case had established "similarities between the two killings, Valentin's murder and my daughter's, especially when it comes to the knife blows."

The French Gendarmerie said that investigators had dealt with hundreds of cases over the past 14 years and some of the killings seemed to match the Valentin case.

The victims did not seem to have anything in common, the gendarmerie said: they include a priest, a transvestite and men and women of all ages.

However, several of the crime scenes had links to Moitoiret and the manner in which the victims were laid out was similar.

Investigators are sure in the Valentin case that it was Moitoiret as they found a knife with both his and Valentin's blood on it in the woods.

The 39-year-old suspect has been travelling around France for 20 years with his partner Noella, who is nine years older than him. The couple said they were on a pilgrimage and they have been staying in church accommodation.

Moitoiret's mother said her son felt persecuted.

"He is a nice boy, but sometimes he lives in another world."

Investigators suspect him of being a psychopath. (dpa)