Like Woody Guthrie, who called his guitar an anti-fascist weapon, the Bangladeshi photographer Shahidul Alam has used his camera for 35 years as a tool to advance social justice. He began by documenting street protests in Dhaka, the capital, in the mid-80s, making pictures in the tradition of the Magnum photographers, especially Henri Cartier-Bresson. But over time, he pushed against the natural constraints of a medium that registers what is seen, so that he might illuminate what is suppressed or has vanished.

“There is a wall in our flat with pictures of friends of ours who have disappeared or been killed,” said Mr. Alam, 64, who was visiting New York from Dhaka recently for the opening of “Truth to Power,” his first retrospective in the United States, at the Rubin Museum of Art, through May 4. “Every so often we add a picture.”

But how does a photographer portray people who have disappeared with hardly a trace? That question, which Mr. Alam addresses creatively in works in this show, ratcheted up to a frightening level last year, when he was arrested and jailed after criticizing the government’s violent response to student demonstrations. “I’ve been photographing the missing and now even the camera was missing,” he said.