A suspect in the murder of rapper Proof -- the D12 rapper and longtime friend of Eminem who was fatally shot during a shootout Tuesday at Detroit club CCC -- turned himself in to police for questioning Wednesday afternoon.

Mario Etheridge, 28, a bouncer at CCC, located on the city's famed Eight Mile strip, met with police accompanied by a lawyer. Etheridge is the cousin of Keith Bender, 35, who police say the rapper shot at the club after an argument over a pool game.

Authorities have now also determined that it was Proof who fired the first bullet.

Proof was among the most revered MCs in Detroit and befriended fellow Motor City rapper Eminem before joining Em's rap troupe D12. He released his solo debut, Searching for Jerry Garcia, last summer on his independent label Iron Fist Records.

Memorial service arrangements are still pending.