The killings of two police officers and a passerby in the Belgian city of Liège on Tuesday are being considered as “terrorist murders”, a federal magistrate has said.
Authorities are now facing questions over why the attacker, named as 31-year-old convicted drug dealer Benjamin Herman, was released from prison for the day.
The Belgian Interior Minister, Jan Jambon, said on Wednesday that the attacker, who is believed to have been radicalised in jail, had already killed another person the day before the attack.
Investigators are also considering whether Herman acted alone, federal magistrate Wenke Roggen said on Wednesday.
At around 10.30am local time on Tuesday, Herman approached two female officers from behind with a knife, taking one of their guns and shooting them both dead.
Soraya Belkacemi and Lucile Garcia have been named as the officers killed in the attack.
Prosecutor Philippe Dulieu said that Herman then walked down the street and shot dead 22-year-old Cyril Vangriecken who was sitting in the passenger seat of a parked car.
Herman later went into a high school, taking a woman hostage and triggering a major intervention by armed police. A gun battle broke out and the attacker was killed. Two other police officers were injured.
The justice minister, who oversees the prison service, said he felt “responsible” for Tuesday’s bloodshed.
“The question of whether this man should have been given leave is striking because he killed three completely innocent people with a wish to kill himself,” Koen Geens told RTBF radio on Wednesday.
“I have to examine my own conscience.”
The attacker shouted “Allahu akbar” several times during the rampage before he was shot dead by police, the Associated Press reported.
Jambon told broadcaster RTL that Herman “also committed a murder the night before” and confirmed that the person killed was a former inmate who was in prison with Herman.
It is alleged that Herman killed a man on Monday evening after hitting him on the head with a blunt object.
Herman was let out of prison for two days on Monday to prepare for an eventual release in 2020.
Unlike after other suspected “lone wolf” attacks in Europe, there has been no claim of responsibility by so-called Islamic State.
Liège is an industrial city close to the German border in the French-speaking Wallonia region.
The city was also the scene of a shooting in 2011, when a gunman killed four people and wounded more than 100 before turning the gun on himself.
Belgium has been on high alert since a Brussels-based Islamic State cell was involved in attacks on Paris in 2015 that killed 130 people and Brussels in 2016 in which 32 died.