Liege shooter Benjamin Herman was on day release from prison when he carried out the attack that killed two policewomen and a bystander on Wednesday.
He is also believed to have killed another man the night before the shooting.
Though no official motive has been given for his actions prosecutors suggested there could be links to terrorism:
"The first elements of the investigation showed that it might be a terrorist attack. These first elements have to be understood as the modus operandi regularly shown on the internet by IS in their video messages: suggesting to attack the police with a knife and rob them of their service weapons. Also the fact that the perpetrator shouted different times Allahu akbar (the Arabic phrase for God is great)," explained Eric Van Der Sypt, spokesman for Belgium's federal prosecutors.
Questions were raised as to whether the Belgian authorities could have done more to spot any signs that Herman was going to carry out such an attack.
”The question is whether the fact that he meets or if he prays in a group for example, is that a sufficient sign of radicalisation to treat him like a dangerous terrorist. And on this we were unequivocal, the answer was no. Maybe we got it wrong, but the answer was no." Koen Geens Belgian Justice Minister said on Belgian radio La 1ere.
Herman had reportedly done various stints in jail since 2003 for assault, robbery and drugs convictions. He was due for release in two years.