Inside the Charlie Hebdo Offices Moments After Attack

A chilling photo of the bloodied Charlie Hebdo office has been released, giving a glimpse into the horror of Wednesday's shooting.

The bloody attack reportedly started on the ground floor, when they killed one of the two doorman in the building after asking where they could find the satirical newspaper's offices.

The assailants were able to get into the offices after forcing a cartoonist, Corinne Rey, to enter the security code by threatening her young daughter, who she had just picked up from daycare, French authorities said.

Inside, editors and contributors were gathered for an editorial meeting, and that is where the string of execution-style killings occurred, authorities said. The tenth fatality inside the conference room was that of the state-ordered bodyguard who was assigned to protect the publication's editor and chief cartoonist, Stephane "Charb" Charbonnier.

Many of the head editors and cartoonists for the newspaper are believed to be among the fatalities, but the full list has not yet been released publicly.

Paris Deputy Mayor Patrick Klugman told ABC News that one of the assailants shot the staffers, including some of the country's best-known political cartoonists.

Ten people -- nine of them staffers or contributors -- were killed inside the office, and two others outside, plus an additional 11 people injured, four of whom were critical in the hours following the attack.

The assailants, believed to be brothers Said and Cherif Kouachi, were only in the office for five minutes before fleeing the scene, authorities said.