Police say one of men, Jerrell Jeter, fired his gun and struck Melenka in the arm. Melenka returned fire, hitting Jeter in the chest and leg.
Jeter was taken to University Hospital, where he died a short time later.
Melenka, a 24-year veteran of the force, was also treated at the hospital and released.
Police say the second suspect, a muscular man in his mid 20s, fled the scene.
Rewards of up to $15,000 are being offered for information leading up to the suspect's arrest.
