French police have Paris gunman's DNA

French police are working on DNA traces left by the lone Paris gunman who has attacked two media houses over the last four days. Although more photos of the suspect have been made public, he remains at large and unidentified.

The latest photo of the Paris lone gunman

A man has been arrested and released in the hunt for the Paris gunman, according to Le Parisien newspaper, which earlier reported his detention.

Several other people have been questioned and let go since Monday's attacks, the paper says.

Officials earlier refused to confirm or deny a report that the gunman has been captured.

"We have no information one way or the other," a source told the Reuters news agency after the Le Parisien newspaper's website reported the man had been arrested in Paris's eight arrondissement.

"In the last few hours a lot of work has been done on this individual's DNA, either in the car he used or on the cartridges," Interior Minister Manuel Valls said Tuesday while he visited an exhibition on internal security in Paris on Tuesday. "We are continuing to distribute all the photos that allow people who know him, his neighbours and the police to recognise him and arrest him."

Police are taking seriously about 120 of the roughly 400 calls they have received from the public after appealing for information and distributing photos taken from closed-circuit TV cameras from the TV channel and newspaper that he attacked and from public transport.

The driver who the gunman took hostage after firing shots at the La Défense business district on Monday was so traumatised by his ordeal that he failed to alert police straight away, while the suspect was still on the Champs Elysées, according to the TF1 TV channel.

The man, a pensioner, returned to his home in a Paris suburb and phoned his son to tell him of his ordeal, TF1 says.

His son told him to turn on his television and see if what he had been through had any connection with the drama being broadcast on all France's news bulletins.

On discovering that was the case, the man felt faint and his son called emergency services and explained what had happened.

Once alerted, police examined the man's Renault Twingo and a sniffer dog followed the man's trail to tha banks of the River Seine.