The man who allegedly stabbed two young women to death in Marseille, France Sunday had been arrested and then released by police two days before the incident.
French authorities said the suspect, who went by multiple identities was stopped by police in Lyon on Sept. 29 for suspected shoplifting, but he was released for a lack of evidence.
The man had reportedly shouted "Allahu Akbar," (God is great) as he stabbed the two women at Marseille's main train station before French soldiers gunned him down.
Islamic State claimed responsibility for the attack through its official news agency.
Police video is said to show the suspect stabbing one woman, disappearing, and re-emerging moments later to attack his second victim.
He ran straight toward soldiers who opened fire and killed him. The attacker and his victims have not been publicly identified.
Police shut down and sealed off the station and French Interior Minister Gerard Collomb immediately went to Marseille.
French prosecutors have opened a counter-terrorism probe, but Collomb has not yet formally declared it a terror attack.
French President Emmanuel Macron tweeted that he is "deeply outraged" by the "barbarous" attack while praising the swift but cool-headed response by the soldiers.
France has been in a state of emergency since November 2015 after Islamic extremists attacked a concert hall in Paris and several bars.
Ten months earlier, gunmen had opened fire in the offices of the satirical cartoon magazine Charlie Hebdo and later seized hostages in a kosher supermarket.
There have been several other terror attacks in France since then, including one in Nice in July 2016 where 86 people were killed when a driver ran down pedestrians celebrating Bastille Day.