SAINT-ETIENNE-DU-ROUVRAY (France) • Adel Kermiche was an attention-seeking child whose behavioural problems led him to a psychiatric hospital and later a specialist school.

He died a cold-blooded killer who slit the throat of an elderly French priest in the name of the Islamic State in Iraq and Syria (ISIS).

The son of a working-class Franco-Algerian family living just outside the Normandy city of Rouen, the teenager flipped between model student and aggressor as a youngster. He blipped on the radar of security services early last year, when he made his first failed bid to reach Syria.

Kermiche burst into a church on the outskirts of Rouen during morning mass last Tuesday with another teenage Islamic militant and killed the 85-year-old priest at the altar, chanting in Arabic, before they were both shot dead by police.

"He was a loner. He was a troubled soul, he was all alone in his head," said a neighbour of the Kermiche family in the leafy Rouen suburb where the 19-year-old was living under a court surveillance order. "All he would talk about was Syria." A judicial source said Kermiche received regular psycho- therapy and medication between the ages of six and 13, at which point he was sent to a school for pupils with behavioural problems.

What role Kermiche's troubled background played in his conversion to a killer is unclear. His radicalisation, however, was swift.

His mother told Swiss newspaper La Tribune de Geneve last year that Kermiche became "bewitched" by hardline Islamic ideology after militants attacked the satirical Charlie Hebdo magazine in Paris in January last year. Two months later, he made his first attempt to reach Syria.

Investigators are digging into the relationship between Kermiche and Abdel-Malik Nabir Petitjean, his accomplice in the church attack, who lived in a French alpine town 700km away from Kermiche, and how the two communicated before staging their attack.

At the local mosque, Mr Mohammed Karabila, head of the regional Muslim council, pointed at a small wall separating the mosque from Saint-Etienne's second church as a demonstration of the harmony between the town's religious communities.

Kermiche, he said, was unknown at the mosque. "We would have liked him to come to the mosque," he said. "But today, these kids' mosque is Google, it's the Internet."

REUTERS