Officers on patrol heard gunshots near 39th and Brown streets just before 5:30 p.m. Sunday.
According to investigators, a 27-year-old and a 21-year-old began fighting, then the 27-year-old shot and killed the 21-year-old.
Police said the alleged shooter and another person with him were taken into custody.
The investigation remains ongoing.
The names of those involved have not been released.