Four cartoonists were among 12 victims killed in a violent armed attack on the offices of Paris satirical newspaper Charlie Hebdo on Wednesday.  The attackers shouted (in French), "We have avenged the Prophet Muhammad.  We have killed Charlie Hebdo," according to a video seen by the New York Times.     

The newspaper has a long history of publishing satirical attacks on religion, including Islam, and has been targeted over its cartoons before, including a firebombing.

The cartoonists who were killed were the newspaper’s editorial director Stephane Charbonnier, and staff cartoonists Jean Cabut, Georges Wolinski, and Bernard Verlhac.  Other victims included other newspaper staffers and police officers.  As of this writing, one suspect has surrendered, and two more are being sought. 

Cartoonists and other artists around the world have published cartoons of their own in response to the attacks, an assortment collected here by the Philadelphia Inquirer, for example.  Street demonstrations also sprang up today around the world, including in the U.S., in support of the newspaper.  Many were using the phrase "je suis Charlie," (I am Charlie) to show their support, and the hashtag #jesuischarlie was trending for a time Wednesday on Twitter.