Kermiche had been arrested twice in both France and Switzerland for attempting to flee France to join ISIS in serious and was being monitored with an electronic ankle tag.
Despite having been released early from prison, Kermiche's bail conditions allowed him to move about freely without supervision between 8.30am and 12.30pm every day.
Kermiche and his accomplice attacked and killed the priest between 9am and 11am. Both of them were shot and killed by police marksmen as they emerged from the building shouting 'Allahu Akbar' following the attack that also left a nun critically injured.
'They told me "you Christians, you kill us". They forced him to his knees. He wanted to defend himself. And that's when the tragedy.Kermiche was living with his parents in Saint-Etienne-du-Rouvray with his parents.
In a press conference, the police said they are still seeking to identify the second attacker and raids were underway.