PARIS (AP) - A suspected French jihadist who spent time in Syria has been arrested over the shooting deaths of three people at a Belgian Jewish museum, prosecutors said Sunday, crystalizing fears that European radicals will parlay their experiences in Syria into terrorism back home.
When Mehdi Nemmouche was arrested in southern France on Friday, he was in possession of firearms, a large quantity of ammunition and a video claiming responsibility for the May 24 attack at the Jewish Museum in Brussels, a Belgian prosecutor said.
In a one-minute rampage that deeply shook Europe's Jewish community, a gunman opened fire at the Brussels museum. In addition to the fatalities, another person was gravely wounded.
Authorities raised anti-terror alert levels as they searched for the attacker. But it was ultimately a customs inspection in the French port city of Marseille that turned up Nemmouche, as he disembarked from a bus coming from Amsterdam, Paris prosecutor Francois Molins said.
The suspect had a revolver and a retractable automatic weapon like those used in the Brussels attack, and ballistics analyses were underway to determine if they were the same weapons, Molins said.
At least one of the weapons was wrapped up in a white sheet scrawled with the name of the Islamic State of Iraq and the Levant, an extremist group fighting in Syria, Molins said. The group has also waged attacks in Iraq.
Nemmouche, a French-born 29-year-old from the northern city of Roubaix, had a criminal record, with seven convictions for crimes like attempted robbery - but nothing related to terrorism, Molins said.
He said the suspect became radicalized in prison, and left for Syria just three weeks after his last prison stay in late 2012, going to Syria via Brussels, London and Istanbul. He said the suspect had spent about a year in Syria, though it is unclear why he went and what he did while there.
A video found in the suspect's possession shows weapons and clothes akin to the gunman's, and includes a voice claiming responsibility for the "attack in Brussels against Jews," Belgian federal prosecutor Frederic Van Leeuw said. He said it wasn't certain whether the voice was that of the suspect.
The narrator says he tried to film the killings on May 24 live, but that his camera failed, Van Leeuw said. When apprehended, the suspect had a GoPro camera in his possession, the Belgian prosecutor said.
Belgian police carried out raids in the Courtrai region of Belgium on Sunday morning, where the suspect is believed to have spent time, and were questioning two people there, Van Leeuw said.
The suspect has been handed to anti-terrorist investigators and could be held at least through Tuesday under French counterterrorism law.
"The new elements in this investigation draw attention once more to the problem of the 'returnees' -in other words the people going to Syria to participate in combat and return afterward to our country," Van Leeuw said.
Interior ministers from around the European Union are expected to focus on better ways to stem Syria-related violence when they meet in Brussels on Thursday.
French Interior Minister Bernard Cazeneuve called Sunday for better international coordination on the issue. His Belgian counterpart, Joelle Milquet, called the returnees "a generalized problem for all of Europe."
The Brussels killings, which came on the eve of European Parliament elections in which far right parties had a strong showing, led Belgian officials to boost their anti-terror measures, and raised fears of rising anti-Semitism.
Two Israeli tourists and a French citizen were killed in the museum attack, and a fourth victim remains hospitalized hovering between life and death, the Belgian prosecutor said Sunday.
The European Jewish Congress welcomed the arrest and urged European authorities to act faster and more aggressively to prevent such crimes.
The suspect has said nothing to investigators so far during his interrogations, Molins said.
Nemmouche's former lawyer, Soulifa Badaoui, described him on BFM television as someone "in difficulty" who went from foster home to foster home and often lived in vehicles. She said he was an intelligent person with serious family problems.
The attack and the arrest highlight the challenge for European authorities in tracking homegrown extremists, often alienated youths from immigrant backgrounds with few job prospects, when they travel to and from Syria.
French President Francois Hollande promised Sunday to "fight" homegrown radicals who come home from Syria with violent plans.
France has western Europe's largest Muslim population, and while it is overwhelmingly moderate, authorities say several hundred French people have left to join Islamic radicals fighting against Syrian President Bashar Assad's army.
The French government recently introduced measures to try to stop disaffected youth from leaving in the first place, and better track those who go to Syria and come back.
"The whole government is mobilized to follow the jihadists, and prevent them from being able to cause harm" especially when they come home to France or elsewhere in Europe, Hollande said on an official visit to Normandy.
The attack and the arrest revived memories of Mohamed Merah, a Frenchman who trained with extremists in Afghanistan and Pakistan, and then attacked a Jewish school and French paratroopers in southern France in 2012.
He killed seven people, including three children in an attack he captured on camera, before dying in a shootout with police. Those killings rocked France, prompting tougher anti-terrorism measures aimed at better tracking French citizens who pursue extremism abroad.
John-Thor Dahlburg reported from Brussels. Angela Charlton contributed from Paris.
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