Documentary filmmaker David Hamlin recalls the adrenalin rush when he was flying over the Democratic Republic of the Congo’s Garamba National Park in late June and spotted three giraffes standing in a small clearing. “Seeing these giraffes from the air was really exciting,” says Hamlin, who was on assignment for National Geographic. “Seeing them anywhere is really exciting.”

That’s because Garamba is huge, sprawling over nearly 2,000 square miles (5,180 square kilometers) of mostly forested land, and it's a rare, lucky event to come across any of its 40 remaining giraffes.

But Hamlin’s exhilaration at seeing and photographing the giraffes didn’t last long. Twelve hours later rangers reported hearing gunshots, and they later discovered three bullet-riddled giraffe carcasses rotting in the sun.