BRUSSELS — Suspected Brussels suicide bomber Najim Laachraoui was a nice, intelligent boy and gave no warning signs of being radicalized before he left for Syria in 2013 and broke all contact with his family, his brother said Thursday.
Laachraoui, a 25-year-old Belgian, is believed to have blown himself up in Tuesday's bombings at the Brussels airport, intelligence sources have told NBC News. He is also suspected of making explosive belts for last November's Paris attacks.
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No one in Laachraoui's family saw any change in his attitude before the day he called them to say he had left for Syria, his 20-year-old brother Mourad said in a news conference.
"He was a nice boy, and above all he was clever, that's what I remember of him," Mourad said of his brother. Najim had studied electromechanics, and looked "normal" the last time Mourad saw him, the brother said.
In 2013, Najim told his family he'd traveled to Syria, and the family warned police, Mourad said. Officers visited them at the time and returned after the November 2015 Paris attacks to search their home.
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Traveling under the false name Soufiane Kayal, Laachraoui was documented driving from Hungary into Austria in September in a car driven by Salah Abdeslam, the prime suspect in the Paris attacks who was arrested in Brussels last week.
Mourad is a taekwondo athlete who has represented Belgium in European and world competitions, said he was deeply saddened by the November attacks. He said he never saw his brother with suspected organizer Abdelhamid Abaaoud, another Belgian, or anyone else involved in the attacks on Paris or Brussels .
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Mourad's lawyer, Phillipe Culot, said: "It's crazy, really — the same parents, the same upbringing, and one turns out really well and the other really bad. Mourad and his whole family are crushed that Najim could have committed such a barbaric act."
"You don't choose your family," Mourad said.
He added that his family has received no official word that Najim is dead.
Earlier on Thursday, the director of a Brussels Catholic high school in Brussels told Reuters that Najim Laachraoui had been a model student there.
"He never failed a class," said Veronica Pellegrini, the director of the Institut de la Sainte Famille d'Helmet, a Catholic school in the ethnically mixed east Brussels borough of Schaerbeek.
Pellegrini said Laachraoui graduated in 2009. "We haven't heard from him since," she said.
Catholic religion classes are part of the school's curriculum for all students regardless of their religion and Laachraoui would have attended those classes as any other student, Pellegrini said.
It is not uncommon for Muslim pupils in Belgium to go to Catholic schools, which can be seen as more conservative or more exclusive than state schools.
