Convicted Dutch terrorist Jason Walters, who has spent eight years in jail for throwing a hand grenade at police, has been released after serving two-thirds of his sentence, the public prosecution department confirmed on Saturday.

Muslim convert Walters, who has an American father and Dutch mother, was arrested in 2004 as one of a group of young men said to have formed a terrorist organisation, known by the police as the Hofstad group.

He was convicted of throwing the hand grenade at police while resisting arrest and sentenced to 13 years in jail. That was later reduced slightly on appeal. Walters, who has since rejected Islam, was 19 at the time.

‘It is only logical that he is allowed out on leave,’ Walters’ lawyer Bart Nooitgedagt said in January, when he successfully applied for prison leave. ‘He has rejected his earlier ideology and repeatedly offered his excuses. He is not mad and he knows if he does not come back or misbehaves his release from jail is at risk.’

Walters has been allowed out early for good behaviour. His release is subject to strict conditions and compliance will be monitored by the probation services, the public prosecution department said.