Belgian investigators said they have discovered a "last testament" attributed to Brussels and Paris attacks suspect Mohamed Abrini, suggesting that he wanted to die a martyr.

Police found the document on a laptop computer discovered on March 22, the day suicide bombers from the Islamic State group launched attacks at Brussels airport and on the Belgian capital's metro which killed 32 people.

The computer was found at one of the hideouts used by the jihadist attackers, according to a Belgian federal police report from April, which AFP gained access to on Wednesday.

Investigators found the Word document dated February 2, 2016 -- over a month before the Brussels attacks -- which they believe is a letter from Abrini to his mother, according to the report.

The letter, written in capitals and littered with spelling errors, "can be considered his last testament" police said.

The author, who calls himself "Abou Yahya", writes that he had travelled to Syria and become "very interested in religion" following the death of his younger brother there.

"After some research, Islamic State (IS) appeared legitimate in his eyes," the police report said.

In March, Belgian police arrested Abrini, a key suspect in the Paris attacks last November in which 130 people were killed.

He also turned out to be the so-called "man in the hat" seen in CCTV footage with two bombers shortly before they staged the Brussels airport assault. 

The Brussels investigators' summary said that Abrini believed the Paris attacks were "just reward from Muslims to France, especially given its participation in the coalition against the Islamic state."

He spoke in the letter of the "heroes...who set off explosions to terrify" the infidels.

"The tone of the letter, as well as its contests, makes it clear the wish of the person to die as a martyr, probably during a future terrorist attack," the investigator said.

Abrini, 31, a Belgian national of Moroccan descent was arrested in Brussels on April 8.

Source: AFP