PARIS — Authorities were scouring Europe on Sunday for at least one other suspect, and possibly two, who were “directly involved” in Friday night’s attacks in Paris, as investigators tried to ascertain whether they were among a number of people arrested over the last 48 hours in Belgium, according to two French officials familiar with the case.
French police took seven people in for questioning Sunday in connection with the deadly siege that killed at least 129 people, expanding an international dragnet and investigation that now stretches from the Aegean Sea to the teeming Paris suburbs. But police continued searching for at least one other participant in the attacks. French officials and the Islamic State both initially claimed that eight men carried out the attacks. Police said seven attackers died, six of them by detonating suicide vests and one in police gunfire.
The seven people taken into custody on Sunday were relatives of Ismaël Omar Mostefaï, a 29-year old French national with a criminal record and one of the seven assailants who died during Friday night’s deadly siege, according to one French police official who spoke on the condition of anonymity. A petty criminal of Algerian descent, Mostefaï was picked up between 2004 and 2010 for eight minor offenses, including driving without a license.
In 2010, however, Mostefaï came on the radar screen of French intelligence because of his associations with radical Islamists at a mosque near Chartres, a city 56 miles west of Paris. He is believed to have traveled to Syria in the winter of 2013. “That is when we lost track of him,” the official said.
“The aim is to figure out what led this man to become a suicide bomber,” the French police official said.
Two people involved in the attacks in Paris were brothers, identified as Ibrahim and Salah Abdeslam, according to a senior European intelligence official familiar with the case. Both were French nationals who have lived for years in Belgium. One of the two was a suicide bomber, while the other helped with logistics and, among other things, rented one of the cars used in the attacks, the official said, speaking on condition of anonymity.
The official identified another assailant as Bilal Hadfi, who also lived in Belgium and investigators confirmed had fought with the Islamic State in Syria.
Mostefaï’s brother, who surrendered for questioning in a southeastern suburb of Paris, confirmed to the Agence France-Presse news service that his younger sibling had committed small crimes in the past. The 34-year-old man, who was not identified, said he had broken off all ties with him years ago. Mostefaï had moved back to Algeria with his young daughter, he added. He said he was shocked to learn that his brother was involved in the attacks.
Police also raided the homes of Mostefaï’s father and of the brother, which were searched during three hours Saturday night by French SWAT teams in Romilly-sur-Seine, a town 79 miles east of Paris, and in Bondoufle, a small suburb in the south of Paris, according to RTL radio.
“What does this have to do with us?” the brother’s wife told AFP in tears. “We haven’t spoken to him in years. I hope we’ll be left alone. We have a quiet little life, and this is starting to worry me.”
The official said another one of the assailants had a Syrian passport, a document that Greek officials have said he used to enter Europe in October on the Aegean island of Leros along with a record flood of refugees fleeing the war-torn Middle East. Sky News later quoted a Greek official as saying the passport was fake, although the attacker probably did use it to pass through Leros.
Investigators were looking into whether a second assailant may have also entered Europe on the refugee route. It immediately raised the prospect that militants may be using the same porous routes into Europe as migrants.
The Serbian Interior Ministry confirmed Sunday that the man who arrived in Greece in October had followed the same path being taken by thousands of desperate asylum seekers looking for refuge in Europe. After arriving in Leros, he went north, transiting Macedonia and entering Serbia on Oct. 7. At the border town of Presevo, a way station for migrants, he registered with Serbian authorities and officially sought asylum. There were no outstanding international warrants in his name.
“Checks have confirmed that his details match those of the person who on October 3 was identified in Greece,” the ministry said in a statement. “There was no Interpol warrant issued against this person.”
A senior European security official speaking on the anonymity said the name in the passport was Ahmad Almohammad. According to the passport, he was 25 and born in Idlib, Syria.
The passport was found at one of the attack sites in Paris — the stadium where French President Francois Hollande was attending a soccer match between France and Germany.
Officials have not conclusively connected the document to one of the two men who blew themselves up at the stadium. But the possible link was enough to ignite fresh calls by some in Europe to end the unprecedented flow of refugees pouring into Europe from war zones in the Middle East.
French police seized one of the vehicles believed to have been used in the Friday night attacks, a black SEAT Leon with weapons inside, in the eastern suburb of Montreuil. Officials sealed off the area with red and white tape as white-clad forensics experts combed the vehicle, a small hatchback built by the Spanish car maker, SEAT.
At least two of the seven dead attackers are believed to be Belgians, including an 18-year-old who had fought in Syria, according to a senior Belgian official.
As of late Saturday, at least 10 suspects were arrested in Belgium.
Three of the 10 were stopped by French police late Friday near the town of Cambrai while attempting to flee into Belgium. The French police had let them pass, but the men were later arrested in Brussels after Belgian authorities raised red flags.
A Belgian official said two of the seven attackers who died in Paris were French citizens living in Brussels, one of them in the neighborhood of St. Jans Molenbeek, the Associated Press reported. The neighborhood is considered a hotbed of Islamist extremism and a source of foreign fighters who have made their way to Syria to join the Islamic State.
On Saturday, Hollande called the attacks an “act of war” by the Islamic State, which issued an extraordinarily detailed claim of responsibility almost immediately after his address to the nation. Left behind after the attacks were the latest scars, Pope Francis said Saturday, from the “piecemeal Third World War.” One survivor described gunmen coldly picking off hostages in a packed concert hall as if “we were birds.”
The attacks — far more sophisticated and more deadly in magnitude than a siege here in January carried out by three Islamist militants — robbed France’s showcase city of its rhythm of life and put Europe on alert to a new level of terrorism. In the aftermath of the most deadly assault on French soil since World War II, the Eiffel Tower was shut down “indefinitely.” The Louvre closed its doors. And the country, which cherishes secular freedoms, outlawed public gatherings until at least Thursday.
France declared a state of emergency — granting police broader powers — for the first time since 2005 riots on the outskirts of Paris. Paris landmarks became ghost towns. The government deployed 1,500 troops to safeguard key buildings. Schools, libraries, food markets, swimming pools and gymnasiums were closed.
About 99 of at least 352 who were wounded — most of them injured during a hail of bullets that hit the front rows of a concert at the Bataclan, where 1,500 fans were listening to the Eagles of Death Metal — remained in serious condition, suggesting that the death toll could increase.
The extent of the violence signaled that the Islamic State is extending its reach far beyond the battlefields of the Middle East, prompting much of the rest of Europe to bolster security on Saturday, ramping up border checks and patrols at key buildings and transit points. But intelligence officials in Germany and Spain said they were focusing mainly on improving security at French schools and embassies, suggesting how France — a nation more involved in fighting Islamist extremism abroad than any of its neighbors — has emerged as the epicenter of the region’s terrorism threat.
“We are facing an act of war organized by an army of terrorist jihadists that had already organized and planned attacks in the past,” French Prime Minister Manuel Valls said Saturday evening. “Five attacks have been thwarted since this summer. But we have always said that there is no such thing as zero risk. We have always said that France could face new terrorist attacks.”
On Saturday, candles and flowers filled an outdoor terrace at La Belle Equipe restaurant, where gunman shot into the crowd. Notes in the flowers included one that read, in French, “To our friend Guillaume full of joy and kindness, may God keep you close to him.”
Another read: “Thoughts for our little Tess and to the children of Lacri. Their parents are in the stars.”
The victims at six attack sites — the Bataclan concert venue, a soccer stadium, and bawdy bars and restaurants in east Paris — included Nohemi Gonzalez, 23, a California State University design student spending her junior year abroad. And Bertrand Navarret, 37, a rock music fan from southern France who was among the first to die as the gunmen fired into the crowd at the concert. And two Tunisian sisters celebrating a friend’s birthday on a night out.
Many Parisians — as they did after the attacks in January — vowed to hold firm. But some also questioned the wisdom of France’s involvement in the Middle East.
“I’m indignant about the foreign policy of France,” Yannis Hassany, 25, a Parisian student of Syrian and Lebanese descent, said Saturday. He was standing near the bloodstained streets of two of the attack sites, Le Carillon bar and Le Petit Cambodge restaurant. “What we’ve done the last four years is responsible for what happened here. France is implicated. France never should have gotten involved in Syria.”
During the attacks Friday, six suspects blew themselves up and a seventh was killed by police. The Islamic State, however, claimed that eight men were directly involved in the attacks.
The siege began at 9:20 p.m. local time Friday and lasted until police stormed the concert hall at 12:20 a.m. The three teams of suicide bombers had spread out across Paris, with two of the groups racing through the city’s streets in the black SEAT León hatchback and a black Volkswagen Polo. They deployed “war-type weapons”: Kalashnikov rifles and explosive belts with identical triggers, said François Molins, a prosecutor in Paris.
The style of weapons indicates that the assailants “wanted to claim as many victims as possible,” he said.
Louis H., a 26-year-old employee at the Bataclan who asked that only his first name and initial be used, said he was attending the concert with his mother. He said the two of them pretended to be dead, lying on the floor for 10 minutes as they heard shots and yelling.
Officials said at least one suspect was a 29-year-old who was eight days shy of his birthday and whom two French media outlets identified as Ismaël Omar Mostefaï. He was the father of a 5-year-old girl and was repeatedly arrested in connection with petty crimes between 2010 and 2015. Le Monde newspaper reported Saturday that Mostefaï was suspected of having traveled to Syria for a few months in the winter of 2013 and 2014.
Officials, however, declined to release the names of any suspects.
“The attacks mean the necessity of an even deeper revision of the European policy toward the migrant crisis,” Konrad Szymanski, Poland’s new European affairs minister, told a local radio station.
French officials recovered fingerprints from at least four of the men, with French, German and other European law enforcement agencies seeking possible matches.
As if in response to the tough declarations from Hollande on Saturday, the Islamic State moments later asserted responsibility for the attacks.
The claim — issued on its internal social media site — said the terrorist group had “precisely chosen targets in the center of the capital of France” and specifically mentioned Hollande’s appearance at the soccer match.
“Let France and all nations following its path know that they will continue to be at the top of the target list of the Islamic State,” it said.
Virgile Demoustier, Emily Badger and Steve Mufson in Paris and Brian Murphy in Washington contributed to this report.