Boris Yaro, a photographer for The Los Angeles Times, wasn’t on assignment on June 5, 1968. But he decided to stop by the Ambassador Hotel in Los Angeles when he heard that Senator Robert F. Kennedy was about to give his victory speech in the hotel’s ballroom after winning the California Democratic presidential primary.

As Kennedy finished speaking, Mr. Yaro retreated to a pantry area, expecting Kennedy to exit through it. He hoped he could snap a photograph or two for his wall at home. Then he heard gunfire — “firecrackerlike” explosions, he remembered.

“I stood frozen as the assailant emptied his weapon,” he recalled in an account published with a photojournalism exhibition at the Fahey/Klein Gallery in Los Angeles in 2018. “When he stopped, I heard a voice say, ‘Get him,’ and several men grabbed him and pushed him down on a metal countertop (or freezer top).

“As the gunman struggled, I saw his weapon come out of his hand,” he continued. “He tried to grab it back. I ducked under the arm of one of the men holding the gunman and picked up the revolver. I remember thinking the grip was very warm.”