French police have said they have the DNA of a gunman suspected of carrying out attacks on two media organisations and a bank, reports Sky News.
A massive manhunt is under way in Paris, a day after the shooter critically wounded a photographer at the offices of major daily newspaper Libération.
Sky's Europe Correspondent Robert Nisbet, in Paris, said: "We're still not entirely sure how they (police) managed to get the DNA.
"We think that it may be because he touched an object inside the car where he took that hostage to drive from the outskirts, the town of Puteaux, into the centre of Paris, the Champs-Elysees where he then melted into the crowd and the metro system."
After fleeing the newspaper's offices in the east of Paris, the gunman is believed to have crossed over to the western edge of the city, where he fired several shots outside the main office of the Société Générale bank. No one was hurt.
He then reportedly hijacked a car driven by a priest and forced him to drop him off close to the Champs-Elysees in the centre of the city.
Le Parisien newspaper earlier reported that the suspected shooter was arrested in the seventh arrondissement of the city, but prosecutors on the case swiftly denied this.
The photographer, who was arriving for his first day of freelance work at the newspaper, suffered wounds to his chest and stomach in the shooting on Monday.
Police also believe the gunman was behind an incident on Friday in which staff members at news television station BFMTV were threatened by a gun-wielding intruder.
In that incident, the gunman emptied several cartridges on the floor, while warning a senior editor: "Next time, I will not miss you."
Investigators have so far been unable to identify the gunman - described as white and aged between 35 and 45 - and branded as a "real danger" by Interior Minister Manuel Valls.
Investigators have issued a new photograph of the suspect taken by a CCTV on Monday in Paris' central Concorde Metro station, near the Champs-Elysées.
Libération executive Nicolas Demorand said the photographer was "still critical", although he was "in a slightly better state".
The newspaper devoted four pages to the unprecedented attack and an employee described the moment the gunman walked in.
Read more of this report from Sky News.