0321 GMT July 21, 2019
Police identified the suspect as Strasbourg-born Cherif Chekatt, 29, who is on an intelligence services watch list as a potential security risk, Reuters reported.
An investigation had been opened into the alleged murder with terrorist intent and suspected ties to terrorist networks with intent to commit crimes, Paris prosecutor Remy Heitz said.
Two people were killed and a third person was brain-dead and being kept alive on life support, he said. Six other victims were fighting for their lives.
France raised its security threat to the highest alert level, strengthening controls on its border with Germany as elite commandos backed by helicopters hunted for the suspect.
French and German agents checked vehicles and public transport crossing the Rhine River, along which the Franco-German frontier runs, backing up traffic in both directions. Hundreds of French troops and police were taking part in the manhunt.
Deputy Interior Minister Laurent Nunez said he could not rule out that the fugitive had already crossed the frontier.
The gunman struck at about 1900 GMT on Tuesday, just as the picturesque Christmas market in the historic city was shutting down.
He engaged in two gunfights with security forces as he evaded a police dragnet and bragged about his acts to the driver of a taxi that he commandeered, prosecutor Heitz said.
No one has yet claimed responsibility, but the US-based Site intelligence group, which monitors terrorist websites, said supporters of Daesh terrorist group were celebrating.
French and German security officials painted a portrait of Chekatt as a serial law-breaker who had racked up more than two dozen convictions in France, Germany and Switzerland, and served time in prison.
“It was during these spells in jail that we detected a radicalization in his religious practices. But there were never signs he was preparing an attack,” Minister Nunez said.
One German security source said the suspect was jailed in southern Germany from August 2016 to February 2017 for aggravated theft but was released before the end of his 27-month sentence so that he could be deported to France.
The attack took place at a testing time for President Emmanuel Macron, who is struggling to quell a month-long public revolt over high living costs that has spurred the worst public unrest in central Paris since the 1968 student riots.
The revelation that Chekatt was on a security watch list will raise questions over possible intelligence failures, though some 26,000 individuals suspected of posing a security risk to France are on the “S File” list.
In recent years, France has been hit by several terrorist attacks.
In 2016, a truck plowed into a Bastille Day crowd in Nice, killing more than 80 people. In November 2015, coordinated terrorist attacks on the Bataclan concert hall and other sites in Paris claimed about 130 lives.