The assailant is suspected of being radicalised in prison by Islamist militants.
As more information emerges about Tuesday’s incident, here is what we know:
At around 10:30 am (0830 GMT), a man followed two female police officers in Liege, stabbed them several times, then grabbed their firearms and shot them both dead. They were 45 and 53 years old.
Officials said the officers were “executed” in a targeted attack.
He then travelled on foot before opening fire on a 22-year-old man in the passenger seat of a parked car, killing him.
The assailant later entered the Leonie de Waha high school in the French-speaking city, where he took an employee hostage.
The high school pupils were evacuated from the rear of the building, and none were injured.
Police officers arrived at the school and the assailant opened fire, wounding several of them in the legs. Officers killed him about 30 minutes after the assault began.
Four police officers were hospitalised with gunshot wounds, including one who was hit in the femoral artery. His life now appears to be out of danger, while another officer has been released from hospital.
The school will be closed on Wednesday and possibly on Thursday. Students will be given psychological counselling.
The case has been classified as a suspected “terrorist offence” and handed to the Belgian federal prosecutor’s office, which investigates terror cases.
The attacker has been identified as Benjamin Herman, according to a source close to the investigation. Born in 1982, he had served prison time for robbery, assault and battery and drug dealing, the source said.
Amateur footage picked up by AFP shows the gunman shouting “Allahu Akbar” (“God is greatest”) as he walked through the streets during the rampage. In another video, a short and intense burst of gunfire is audible, after which the man lies on the ground.
He was last in prison at Marche-en-Famenne, in the French-speaking Wallonia region. Some unconfirmed reports say he had been granted several hours of leave from prison, reportedly to seek work.
The assailant was flagged by the police for having been in contact with Islamist militants in prison where he was radicalised, the source said.