A Belgian federal official says the murder of three people, including two police officers, is now being considered a terrorist attack.

Authorities are now trying to determine if he acted alone.

Benjamin Herman, a Belgian national who was on two-day leave from prison, stabbed two female police officers, stole their weapons and shot them Tuesday, in the city of Liege.

The police officers have been identified as Soraya Belkacemi, 44, and Lucile Garcia, 54.

He also killed a passenger in a car and took one woman hostage inside a school before police killed him in a shootout.

Prosecutors said Herman shouted the Islamic declaration "Allahu Akbar" – which can be translated as "Allah is the greatest" – several times during the murder spree.

Interior Minister Jan Jambon said the woman hostage may have talked Herman down, avoiding more deaths at the school.

"She was very courageous, and perhaps, but this we will have to verify, she helped avoid more victims in the school," Jambon said.

Jambon also confirmed that Herman killed another person Monday night. The fourth victim was a former inmate who served time with Herman. Herman is accused of killing the man by hitting him over the head with a blunt object.

Belgian federal magistrate Wenke Roggen said the attack is being considered a "terrorist murder and attempted terrorist murder."

She said Herman's attack mimicked the Islamic State in several ways. For one, he attacked police with knives and then stole their weapons. He also yelled "Allahu Akbar" like ISIS and was in contact with radicalized people.

Authorities are also investigating to see if he became radicalized during his time in jail.

The Associated Press reports the attack has shaken Belgium yet again as police and military have been working consistently to protect public buildings after the coordinated suicide attacks on the Brussels airport and subway which killed 32 people and injured hundreds of others on March 22, 2016.

"Every morning I am scared that something like this will happen, and every day it happens closer to home," Melissa Lamny said.