The brothers fit what European anti-terrorism investigators call a disturbing but now-familiar profile.
They were young Belgian nationals of Moroccan descent, both with extensive criminal records involving violent crime and guns.
But neither had been previously linked to terrorism, Belgium’s chief prosecutor, Frederic Van Leeuw, said Wednesday at a news conference here.
The siblings — Brahim and Khalid El Bakraoui — were publicly identified Wednesday as two of the suicide bombers in attacks at an airport and on a metro train Tuesday that left 31 people dead and 260 injured, the latest terrorist strikes to stun a continent reeling from violent extremism.
They appear to have been members of a large militant cell with links to November’s attacks in Paris. A third suicide bomber is believed to have been a bomb maker suspected of involvement in the Paris attacks.
The brothers’ path from ex-convicts to Islamic militants and kamikaze killers remained obscure. But authorities have previously watched the radicalization process develop among embittered European youths in prisons and mosques, on the Internet and in clandestine sojourns to war-ravaged Syria.
On Wednesday, Turkish President Recep Tayyip Erdogan told reporters that Ankara had informed Belgian and Dutch authorities in July that one of the Brussels attackers — later identified as Brahim El Bakraoui — had been expelled as a foreign fighter from Turkey, the major crossing point for militants headed to Syria. There was no immediate response from Belgian or Dutch officials.
A day after the bombings at the airport and a metro station, the daytime mood here in the capital was generally somber as heavily armed soldiers and police patrolled the streets and transportation hubs. Under cloudy skies and showers, Brussels took on the feel of a town under siege. Residents expressed fears of future attacks. People waited in long lines to enter train stations amid new security precautions.
“It’s scary, but I think they [terrorists] are probably among us everywhere,” said Stephanie Taibu, 27, a banker who lives in the densely populated Schaerbeek district.
On Tuesday, authorities raided a fifth-floor apartment in Schaerbeek linked to the attacks and discovered bomb-making material and the black flag of Islamic State, the Al Qaeda offshoot that took responsibility for the attacks.
“This doesn’t happen in Belgium,” said a still-disbelieving Taibu. “This happens on TV and in other countries like America.”
Throughout the capital, flags were at half-staff amid an official three-day mourning period.
New police raids were reported in various districts.
An unidentified fourth suspect who fled the airport, leaving behind a bag laden with nails and explosives, is now the target of a massive manhunt.
“It was like something in a movie,” said Jhon Jairo Valderrama, a Colombian immigrant describing the scene on Tuesday as police swept in on the flat next to his apartment on Rue Max Roos in Schaerbeek.
The apartment targeted by police is where authorities discovered bomb-making materials and the militant flag. Residents said the occupants had kept to themselves in what was apparently a safe house rented a month or so ago in preparation for Tuesday’s attacks. No one here seemed to know anything about the shadowy renters of the flat.
A woman lights a candle in the area of the explosion at the Maelbeek subway station in Brussels, Belgium.(JULIEN WARNAND / EPA)
Belgian soldiers gesture for vehicles to keep clear as they patrol near a Brussels court building where Paris terror suspect Salah Abdeslam was expected to appear.
(Peter Dejong / Associated Press)
A Belgian police officer and soldier guard a Brussels court building where Paris terror suspect Salah Abdeslam was expected to appear.
b(Peter Dejong / Associated Press)
A police officer stands guard outside the Council Chamber of Brussels during investigations into the Paris and Brussels terrorist attacks.(Kenzo Tribouillard / AFP/Getty Images)
A woman and children sit and mourn for the victims of the bombings at the Place de la Bourse in the center of Brussels.(Martin Meissner / Associated Press)
Hundreds gather at Place de la Bourse in Brussels to mourn on Wednesday evening.(Martin Meissner / Associated Press)
Brussels Airport workers and relatives pay tribute to the victims of Tuesday’s attacks.(Philippe Huguen / AFP/Getty Images)
Police leave after investigating a house Wednesday in the Anderlecht neighborhood in Brussels, one day after Tuesday’s deadly suicide attacks.(Peter Dejong / Associated Press)
Soldiers and police carry out checks at the Central Station in Brussels on Wednesday, a day after blasts hit the Belgian capital.(Patrik Stollarz / AFP/Getty Images)
Police carry out checks at the Central Station in Brussels on Wednesday.(Patrik Stollarz / AFP/Getty Images)
A woman writes messages in a tribute to the people killed and injured in terrorist attacks at Place de la Bourse in Brussels.(Yoan Valat / European Pressphoto Agency)
A man reacts as people gather to observe a minute of silence in memory of the victims of the Brussels airport and metro bombings, on the Place de la Bourse in central Brussels.(PATRIK STOLLARZ / AFP/Getty Images)
People gather in Brussels to pay tribute to the victims a day after deadly terrorist attacks struck the city.(Aurore Belot / AFP/Getty Images)
People gather around floral tributes, drawings, candles and notes in front of the Bourse of Brussels on Tuesday(AURORE BELOT / AFP/Getty Images)
A woman writes a message on the ground as people leave tributes at the Place de la Bourse following today’s attacks in Brussels, Belgium.(Carl Court / Getty Images)
A security camera photo released on March 22 by Belgian authorities shows three suspects in the attack at Brussels Airport.(AFP/Getty Images)
An unidentified traveler lies on the ground in a smoke-filled terminal after an explosion at Brussels Airport on Tuesday.(Ralph Usbeck / Associated Press)
Two women injured in the explosions at Brussels Airport sit amid shattered glass on Tuesday.(Ketevan Kardava / Georgian Public Broadcaster )
An injured man lies on the floor waiting for aid at Brussels Airport.(Ketevan Kardava / Associated Press)
Smoke fills the terminal at Brussels Airport, where a pair of explosions killed at least 11 people.(Ralph Usbeck / Associated Press)
Brussels commuters climb out of a Metro subway car after an explosion at the Maalbeek station. A series of coordinated explosions ripped through Brussels Airport and the Metro station with dozens killed.(AFP/Getty Images)
Police and rescue teams set up outside the Maelbeek Metro station in Brussels.(Martin Meissner / Associated Press)
Special police secure the Brussels city center as Belgium raised its terror alert to its highest level on Tuesday.(Martin Meissner / Associated Press)
A victim receives first aid from rescuers near Maelbeek metro station in Brussels after an explosion.(Emmanuel Dunand / AFP/Getty Images)
A man with bloodstains on his sweater leaves Brussels Airport following explosions.(Dirk Waem / AFP/Getty Images)
People stand near Brussels Airport after being evacuated.(Geert Vanden Wijngaert / Associated Press)
Passengers are evacuated from Brussels Airport after explosions.(John Thys / AFP/Getty Images)
Emergency rescue workers tend to an unidentified person at the site of an explosion at a metro station in Brussels, Belgium.(Associated Press)
Soldiers block the access to roads close to a metro station in Brussels after a series of apparently coordinated explosions in the city.(Philippe Huguen / AFP/Getty Images)
A victim is evacuated after a explosion in a main metro station in Brussels.(Virginia Mayo / Associated Press)
Passengers leave Brussels Airport after explosions prompted an evacuation.(Laurent Dubrule / European Pressphoto Agency)
A woman is evacuated in an ambulance after a explosion in a Brussels metro station Tuesday.(Virginia Mayo / Associated Press)
People are evacuated from Brussels Airport on Tuesday following explosions.(Dirk Waem / AFP/Getty Images)
A man is wounded after explosions in Brussels Airport on Tuesday.(Ketevan Kardava / Georgian Public Broadcaster)
A Belgian police vehicle drives past passengers who are evacuating the Brussels Airport.(Jonas Roosens / AFP/Getty Images)
People walk away from Brussels Airport on Tuesday after it was rocked by explosions.(Geert Vanden Wijngaert / Associated Press)
All flights were canceled at Brussels Airport after two explosions rocked the main hall.(AFP/Getty Images)
The Brussels attacks and the Paris terrorist strikes appear to involve many such safe houses. The practice is an example of the perpetrators’ skill at terror tradecraft, investigators say.
“Suddenly we discover that terrorists were living next door to us and making bombs,” said a stunned Valderrama, an out-of-work theologian who resides in the apartment with his wife and two teenage daughters.
“My family doesn’t want to live here anymore,” he told a gaggle of journalists gathered outside the apartment building. “Who would ever imagine something like this here in Brussels?”
Leading police to the Schaerbeek flat, Belgian authorities said, was a taxi driver whose small car may have inadvertently saved many lives. After the attacks, officials said, the cabbie came forward and said he had taken three men — apparently the assailants — lugging heavy bags to the airport from Schaerbeek.
“Perhaps I had two or three terrorists in my taxi. I need to tell somebody,” he told police, the Belgian chief prosecutor recounted to reporters Wednesday.
The driver said the men sought to stuff more bags into the taxi but were able to fit only three. The suitcase they left behind in the apartment contained the heaviest load of explosives, the prosecutor said.
In a waste bin at the flat, investigators said, they found a laptop containing a kind of last testament from Brahim El Bakraoui.
Fingerprints and DNA evidence were used to identify the two brothers, authorities said.
Brahim El Bakraoui, 29, was captured on surveillance video as he walked through the departure terminal at Brussels Airport shortly before the 8 a.m. explosion there. He was flanked by two men, all pushing luggage trolleys, in a security camera image released by officials. A separate bombing on a train at the Maelbeek metro station was the work of 27-year-old Khalid El Bakraoui, the prosecutor said.
According to news accounts here, the brothers had served time after being convicted in connection with violent crimes unrelated to terrorism.
Khalid El Bakraoui was sentenced to five years in prison for his part in an armed car-jacking, Belgian media reported, and Brahim El Bakraoui received a nine-year sentence in 2010 for participating in an armed robbery during which a police officer was injured. It was unclear why Brahim El Bakraoui was released before completing his term.
Various connections are emerging between the Brussels attacks and the Nov. 13 strikes in Paris that killed 130 and injured hundreds, authorities say. In Paris, teams of Islamic State operatives with links to Belgium and Syria struck at cafes and a music hall. Much of that operation may have been planned in Brussels, authorities say.
But a U.S. official confirmed Wednesday that Laachraoui was one of the suicide bombers at Brussels Airport. “We have no reason to doubt” reports that he was killed, the official said.
Laachraoui’s DNA has been linked to explosives used in the Paris rampage, said the official, who spoke on condition of anonymity in discussing internal assessments. Laachraoui’s exact role in producing the Paris bombs is unclear, the official added, and he may not have been the only bomb maker in the cell.
The bombings shocked this staid and stately city, which in effect serves as the capital of the new Europe. But residents have demonstrated a resilient spirit, with more than 1,000 gathering late Wednesday in central Brussels’ Place de la Bourse to sing songs, reflect on the attacks and insist that terrorism would not damp their spirits.
“We’re from Brussels and we all live here and we think this is important,” said Christine, 36, a member of a choir called Stemmer whose members were singing songs about Brussels and Belgium; she declined to give her last name. “We’re proud of our city.”
Just a few dozen yards away, near the stock exchange building, another group of young people was sitting around a guitar player singing rock tunes in French. The heavily armed soldiers who guarded the area Tuesday were nowhere to be seen.
“We’re just a little country,” said Sael Menteges, 21, a travel agency worker wearing a sign reading “free hugs,” mimicking similar signs seen in Paris after the November attacks.
“I’ve never seen so much solidarity in Brussels,” Menteges, said. “We are just part of one single humanity tonight. We are just one. We’re not Arabic or Muslim or Christian. We’re just one people.”
Jamal Sahi, 40, an engineer who came from Morocco 13 years ago, agreed.
“We’re not going to stop our way of life because of these stupid terror attacks,” said Sahi, voicing a widely shared sentiment. “People have to show that life is going to continue here and that’s really good.”
Kirschbaum is a special correspondent. Contributing to this report were Times staff writers Brian Bennett in Washington and Corina Knoll in Los Angeles and special correspondents Sheldon Chad in Brussels and Christina Boyle in London.
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