It’s unclear if the two men — a New York City correctional officer and a motorcyclist — knew each other when they met along a quiet roadway in the Jamaica section of Queens early Friday morning, the police said.

The correctional officer, Jonathan Narain, was on his way to work at Rikers Island when he stopped at a store for food. What happened next has shaken not only his family and friends, but also the entire Department of Correction.

The police said Officer Narain got back into his red Honda Accord and made a U-turn when he encountered a motorcyclist. The two exchanged words, the police said. When Officer Narain stopped at a red light a couple of blocks away, the motorcyclist pulled up next to Officer Narain’s vehicle, the police said. Then the men exchanged words again for a few seconds, the police said, and that’s when the motorcyclist fired a single shot into the left side of the officer’s head, killing him.