Officer Michael Yount was responding to a reported burglary in June when three men attacked him, police said. The men also kicked and punched Yount's K-9, Tricky, police said.
Yount eventually fired a shot and struck one of the men in the leg, police said.
The Cumberland County District Attorney's Office ruled that Yount's actions were justified.
Brothers Danny Corey Williams, 19, and Tremayne Quartez Williams, 21, both of 2103 Woodbine Ave., were charged with assault on a government official, injury to personal property and assault on a police K-9. A 15-year-old also was charged in the case.