Two gunmen opened fire outside an event in Garland, Texas which was exhibiting drawings of Muhammad. The event featured Dutch parliamentarian Geert Wilders.
A security guard was wounded, but was released from hospital. Local police shot and killed the two gunmen. Their identities have not been released as of this writing.
In January, 12 people were killed at the offices of Charlie Hebdo in Paris followed by an attack at a free speech conference in Denmark in February that left one person dead. Cartoonist Lars Vilk was the apparent target of the attack.
This is a global campaign of intimidation. The only answer to it is to have more of these exhibits.