It began with an introduction of the defendants followed by the prosecution reading out its 184-page statement detailing the investigation, according to Belgian news agency Belga.
The attack is considered one of the first claimed by the "Islamic State" (IS) militant group on European soil. More than 100 witnesses are expected to testify, including four French journalists who say they were held captive in Syria by one of the perpetrators.
- Mehdi Nemmouche, a 33-year-old French citizen with Algerian heritage, is suspected of opening fire at the museum, first with a pistol and then with an assault rifle. Prosecutors say they have video footage to prove it.
- Four people were killed in the attack, including an Israeli couple, a Belgian receptionist at the museum and a French volunteer.
- Nemmouche was arrested a week later in the French port city of Marseille. Investigators said he was detained while carrying the weapons used in the attack.
- A second suspect, 30-year-old French national Nacer Bendrer, is believed to have supplied the arms, according to prosecutors. Both men are believed to have met in prison, where they were radicalized.
'Terrorist murder'Both men have been charged with "terrorist murder." Both deny any wrongdoing.
At least 120 witnesses are expected to testify during the trial. Prosecutors will begin cross-examining the suspects on Tuesday.
If convicted, both suspects face potential life sentences. The jury consists of four women and eight men.
Read more: Are Europeans getting used to terror attacks?
Terror attacks in EuropeThe shooting is part of a series of terror attacks that swept across several Western European capitals, many of them claimed by IS.
Nemmouche is believed to have fought with an Islamist group in Syria from 2013 to 2014 — key witnesses in the case are expected to say they recognize him as their IS jailer. While in Syria, he met Najim Laachraoui, who formed part of the gang-turned-terror cell that committed the 2016 Brussels attacks that killed 32 people.
The Belgium-based gang is allegedly responsible for partly coordinating the Paris attacks that killed 130 people in 2015. Both attacks were claimed by IS.
Terrorism expert Thomas Renard of the Egmont Institute told DW that, in retrospect, it is clear that the Brussels attack was the first in a long series carried out by terrorists who trained in Syria.
"The trial in Brussels is not only symbolically important, but it is also important in helping us learning about the targeting, planning and execution of attacks," he said. "It can illuminate the phenomenon of a brand of terrorism that has shaken not only Belgium but all of Europe."
Renard cited the attack on the Jewish Museum as a precursor to others, such as the attack on the offices of satire magazine Charlie Hebdo, a Jewish supermarket, a concert venue and restaurants in Paris, on pedestrians in Nice, and subway as well as an airport attack in Brussels.
More than 260 people were killed in attacks in France, Belgium and Germany between 2014 and 2016.
Pascale Falek, director of the Jewish Museum, told DW that the trial will be a "difficult and painful" experience, "Our world was changed — that of the Jewish community, but also that of Belgium as a whole."
Read more: Opinion: The normality of terrorism
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ls/sms (dpa, AFP)