Police responded to a call about a shooting in the 4000 block of Fairfield Ave South around 7:15 a.m. Monday.
Officers found 40-year-old Ronald Gary, who had been shot several times. He was taken to a nearby hospital with critical injuries, but died hours later.
Police said 17-year-old Keyshawn Smiley, the victim's cousin, lives in the same home.
After the two got into an argument, officers said the teen shot the victim multiple times.
Police arrested Smiley and charged him with first-degree murder.