By Ingrid Melander
Brussels suicide bomber Najim Laachraoui was a nice, intelligent boy, his brother says, and gave no warning signs of being radicalised before he left for Syria in 2013 and broke all contact with his family.
Laachraoui, a 25-year-old Belgian, was one of Tuesday's suicide bombers, security sources have told local media. A veteran Islamist fighter in Syria, he is also suspected of making explosive belts for last November's Paris attacks.
No one in the 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. They also have no clue as to what could have led him to be radicalised, he said.
"He was a nice boy, and above all he was clever, that's what I remember of him," Mourad said of his brother, who graduated in electromechanics. The last time he saw Najim, he told a news conference, he looked "normal".
The family warned the police in 2013 when Najim told them he was in Syria, Mourad said. The police visited them at the time and came back to search their home after the November 2015 Paris attacks.
Mourad, who said he was deeply saddened by the November attacks, said he never saw his brother with their suspected mastermind Abdelhamid Abaaoud, another Belgian, or anyone else involved in the Paris or Brussels carnage.
Najim was religious, as was the family, Mourad said, adding that he would do everything possible to make sure his three younger siblings still at school did not become radical.
Belgium's ABFT taekwondo federation said on its website Mourad is a taekwondo athlete who had represented Belgium in European and world competitions, .
"It's crazy, really - the same parents, the same upbringing, and one turns out really well and the other really bad," Mourad's lawyer Philippe Culot said. "Mourad and his whole family are crushed that Najim could have committed such a barbaric act."
Mourad remarked, "You don't choose your family."
Authorities had not officially said Najim was dead and his family had had no confirmation either, Mourad told journalists.
Najim Laachraoui was a model student in a Brussels Catholic high school, its director told Reuters earlier on Thursday.
"Najim Laachraoui was a very good student," 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.
"He never failed a class," Pellegrini said of Laachraoui, who studied at the school for six years, until graduating in 2009. "We haven't heard from him since," she said.
Travelling 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.
There is speculation Laachraoui had just returned from Syria, possibly by sea with refugees.
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.
Belgium has lowered its security alert level one notch down from four, the highest level, to three, two days after bombings in Brussels killed 31 people, the Belgian crisis centre says.
The body composed of top ministers, police and justice officials did not say what that would mean in terms of security measures.
Belgian prosecutors have confirmed they issued an international arrest warrant in December for one of two brothers blamed for deadly bomb blasts in Brussels this week because he was wanted in connection with last year's Paris attacks.
Khalid El Bakraoui, 27, blew himself up on a crowded rush hour train in Brussels on Tuesday, prosecutors said.
They confirmed in a statement on Thursday that he was previously suspected of using a false identity to rent a property in the Belgian city of Charleroi, which was used as a safe house by members of an Islamist cell that carried out the November 13 Paris attacks that killed 130 people.
Belgian police searched the property on December 9 and issued an international arrest warrant for Bakraoui on December 11.
His details and photo appear on a list of wanted people on the website of Interpol.
Prosecutors say his brother Ibrahim, 29, had been one of two men who blew themselves up at Brussels airport in the co-ordinated attacks on Tuesday.
The suicide bombers who blew themselves up in Brussels were reportedly originally considering an attack on a nuclear site in Belgium. It's believed arrests started last week may have forced them switch to targets in the Belgian capital.
The Belgian DH newspaper reported last December that militants had filmed the home of an unidentified senior official in the nuclear industry last December. A 10-hour video from a camera hidden in front of the nuclear official's house was during a police raid in Belgium, linked to the Paris attacks a month before.
DH has now quoted a police source as saying two of the Brussels suicide bombers, brothers Khalid and Ibrahim Bakraoui, were those who had filmed the daily routine of the head of Belgium's nuclear research and development program.
In February, Belgian prosecutors confirmed the existence of the video seized in December and said the man in it was linked to the country's nuclear industry.
Earlier this month, 140 soldiers were dispatched to guard the country's three nuclear sites.
On Tuesday after the Brussels bombings, the sites were sealed and non-essential staff evacuated as a precaution.
The taxi driver who drove the Brussels suicide bombers to the airport was not allowed to touch their explosives-laden bags and they sat in silence during the journey, Belgian newspaper DH reports, citing unidentified sources.
Brahim El Bakraoui and two other men suspected of carrying out the attack on Tuesday, travelled from the Brussels district of Schaerbeek to the airport.
The airport bombs and a suicide bombing at Maelbeek metro station in the city centre, which prosecutors said was carried out by El Bakraoui's brother Khalid, killed at least 31 people and injured 270.
A man wearing a hat and light-coloured jacket did chat with the taxi driver, talking about his anger towards the United States and how he disagreed with some of its actions, DH said.
A bespectacled man wearing a cream jacket and black hat ran out of the airport terminal, federal prosecutors said, before a third suitcase bomb exploded in the departures area as bomb disposal experts were clearing the area, causing no casualties.
The man who ran, captured on film with the suicide bombers, is being sought by police.
DH said the taxi driver smelled ammonia during the journey and when he dropped the men off at the airport noticed their bags had traces of white powder on them.
He heard about the explosions while driving his next passenger and immediately went to the police, the newspaper said.
On Wednesday, a mix-up by a Brussels taxi dispatcher meant a small car was sent to pick up the bombers instead of the minivan they had ordered and the passengers were forced to leave one bag behind.
Police later found a nail bomb in an apartment in Schaerbeek.