Chilling image reveals aftermath of Paris massacre

The first photograph has emerged of the Paris offices where 12 people were slain, as police close in on their killers.

The chilling image depicts a narrow corridor with blood-stained wooden floors and papers strewn across the floor.

In the far back corner an coat rests over the chair of its owner and beneath it a crimson pool, from which smeared footprints snake down the hall.

Pinned to the walls of the haunting murder scene are the very cartoons from the pages of Charlie Hebdo that plunged the French satirical newspaper into notoriety.

Charlie Hebdo's staff had been the target of death threats for years, starting in 2006 when it reprinted 12 cartoons of Islam's Prophet Mohammed published the previous year by the Danish newspaper Jyllands-Posten.

Even though the paper was under police protection, two masked men wielding assault rifles were able to carry out Wednesday's methodical, military-style attack and escape.

The magazine's editor, publisher and cartoonist, Stéphane Charbonnier, pen name "Charb", was killed Wednesday alongside nine others in the newsroom.

Four cartoonists — Jean "Cabu" Cabut, Bernard "Tignous" Verlhac, Georges Wolinski and Philippe Honore — also died in the attack.

A twelfth victim, Muslim police officer Ahmed Merabet, was gunned down outside the office.

The cartoon-reliant newspaper – with a name inspired by the American comic book character Charlie Brown from the series "Peanuts" (with "Hebdo" being French slang for weekly) – will next week bring out a special "survivors'" issue of eight pages instead of its usual 16, AFP reports.

It is anticipated to print one million copies, more than 20 times its average weekly circulation of 45,000.

The leftwing French daily newspaper Liberation will host Charlie Hebdo's journalists from Friday, because the weekly's own blood-soaked, bullet-riddled offices are sealed after the attack.

France's Le Monde newspaper and Canal+ television network are also providing assistance.

Meanwhile, French authorities have surrounded the Forêt de Retz, a 132 square km forest outside of Paris, where they believe brothers Cherif Kouachi, 32, and Said Kouachi, 34, are hiding.

Police are yet to confirm whether the alleged terrorists were behind a service station hold up, during which two men armed with AK47s, rifles and rocket launchers burst into the Avia servo in Villers-Cotteret Thursday morning.