Traces of DNA on an orange juice bottle and a surveillance video of a man praying in a mall have led to the arrest of a young suspect accused of stabbing a French soldier who was patrolling a crowded area just outside Paris.
The attack came days after a British soldier was slain on a London street in broad daylight, raising fears of potential copycat strikes.
The French suspect, identified only by his first name Alexandre D, was captured on camera Saturday offering a Muslim prayer in a corner of a busy shopping mall 10 minutes before he went after the soldier with a knife in the La Defense financial and shopping district.
The suspect fled the area after the incident but detectives said they had obtained "high-quality images" of him. A bag that he was carrying was found on the first floor of the centre.
Inside the bag, police found a pullover, a knife in a case, a second, empty knife case, and a bottle of orange juice that had been opened.
Prosecutor Francois Molins said the 22-year-old suspect was arrested yesterday outside Paris at the house of a friend who has not been implicated.
The French soldier, Private Cedric Cordiez, is recovering from his injuries and has been released from hospital.
"The suspect implicitly confessed when he told police, 'I know why you're here,"' Molins said yesterday at a news conference in Paris. "Given the attack in London, immediately Saturday we considered the possibility this was terrorism."
The suspect, who was unemployed and homeless, was identified through DNA he had left on the plastic juice bottle and already known to law enforcement for his ties to radical Islam, said Christophe Crepin, spokesman for the police union UNSA.
Molins said the man first came under scrutiny after a street prayer in 2007 and authorities had his DNA profile.
The prosecutor said the suspect was seen on video surveillance camera "saying a Muslim prayer" minutes before an attack on the soldier who was on patrol with two colleagues. The video footage also showed the suspect buying two knives an hour before the attack.
"That leads us to believe he was acting on the basis of religious beliefs," Molins said.
"It seems clear the intent was to kill."
Molins said the suspect had shown an "impressive determination" to carry out the attack, stabbing the soldier "several times" with a fold-out knife.
The suspect was known to police for various petty offences but did not have a criminal record. The head of investigative police, Christian Flaesch, said there had been no previous indications of the suspect's involvement in violent extremism.
"Other than the praying in the street, there were no other elements that could have indicated he was dangerous," Flaesch said, adding that the man was from a "family that seems completely honourable".
Under French anti-terrorism law, he can be held for 96 hours without charge.
France has been on high alert since its military operation to drive Islamic extremists out of Mali began in January, sparking threats of reprisals from al-Qaeda in North Africa.
On May 7, a gendarme in the southeastern Isere region was injured after a man entered a gendarmerie and pulled out a knife, shouting "Allah is great", before stabbing the officer three times in the neck, the forearm and the leg.
The attacker, reported to have recently returned from a pilgrimage to Mecca, was shot in the legs and taken to hospital and is under investigation for attempted murder.
Last year, three French paratroopers were killed by a man police described as a French-born Islamic extremist. Mohamed Merah went on to attack a Jewish school in southwest France, killing a rabbi and three Jewish children in March 2012 before being killed later that month in a gunbattle with police.
"I have said before there are dozens, if not hundreds of potential Merahs in our country," Interior Minister Manuel Valls told the iTele network.
Associated Press, The Guardian, Reuters, Agence France-Presse