BOSTON — The U.S. Postal Inspection Service is offering a $50,000 reward for information about the shooting of a letter carrier in the Dorchester section of Boston.

Boston police say a masked man who appeared to be in his 20s jumped into the letter carrier’s Postal Service truck at about 6 p.m. Friday. Authorities say the suspect demanded something, hit the postal worker in the head, made him take off his uniform and tried to drive away in the truck.

Police say the letter carrier was shot in his right hand or wrist during the struggle and escaped from the truck, which was found a short distance away. The postal worker was treated at a hospital for a serious injury.

Postal inspectors have talked with employees about security protocols and safety tips.