From TheAtlantic.com:

Freelance photographer Anton Lazarus Hammerl, a South African who also held Austrian citizenship, was killed in Libya on April 5, his family has just learned. Hammerl was traveling with three other journalists outside of Brega when the group was attacked by government troops, who shot and killed him. Until this evening, when Hammerl's family announced his death in a post to the Facebook group "Free photographer Anton Hammerl," he was believed to be alive and detained by the Libyan government.

Upon crossing the border into Tunisia on Thursday, the other journalists communicated the news of Hammerl's death to his family through an intermediary. Clare Morgana Gillis, who contributes to The Atlantic and USA Today; James Foley of GlobalPost; and Spanish photographer Manuel Brabo were all with Hammerl when he was killed.

Max Fisher's report continues here.