METZ -- A 31-year-old Frenchman sent back to prison for the murder of two children after being found guilty at a retrial -- 14 years into his sentence -- will try again to clear his name, AFP quoted his lawyer as saying on Monday.

The guilt of Patrick Dils, who was 16 when the two eight-year-olds were beaten to death, came into question after it emerged that a notorious serial killer was working nearby at the time of the killing.

The jury at his retrial caused surprise on Friday when it found him guilty and sent him back to jail to serve a 25-year sentence, despite both prosecutors and defense lawyers agreeing that evidence against him was faulty.

Arrested shortly after the crime, Dils initially confessed to crushing the two boys' skulls with stones, but he later retracted his statement and his family has since been fighting to clear his name.

Three years ago Dils's lawyer discovered that Francis Heaulme, a 41-year-old former vagrant now serving a life prison term for five murders, had been in the eastern village of Montigny-les-Metz the day of the killings, and working just a few hundred meters from where they took place.

Heaulme gave evidence as a witness at the retrial earlier this week, and denied that he had killed the boys. His lawyer insisted there was no evidence other than his presence linking him to the crime.

The jury also ruled out trying Dils as a minor, despite his age at the time of the killings and the public controversy triggered by the case.

On Sunday the daily ***Le Parisien*** said: "The Dils case was already an unusual trial, and now it has become an enormous scandal. Everything in the case is exceptional or unprecedented. The debate on the innocence or guilt of Dils is not over."

After his new conviction Dils said: "I haven't fought for 14 years to finish here. I'll keep going."

Paradoxically, in bidding to be tried a third time, Dils risks extending his jail term, as in serving 14 years of a 25-year sentence he could expect to receive parole before the likely date of a new trial.

Defense lawyer Bertrand Becker, announcing the appeal, said: "You don't compromise with truth and innocence. He could be freed, but that doesn't interest Patrick, who wants to prove his innocence."