Proof, a member of rap group D12 and a close friend of Eminem, was shot to death April 11 at a nightclub along Detroit’s Eight Mile, the road made famous by the 2002 film that starred Eminem and in which Proof had a bit part.

Proof, whose real name is Deshaun Holton, was one of two people shot in the head after an argument escalated into gunfire, said Detroit police spokesman James Tate.

The other person — a 35-year-old man — was critically wounded, Tate said.

D12, whose members include Eminem, has been around since the mid-1990s, when members of the rap group met at Detroit’s Hip-Hop Shop, a clothing store by day and a hip-hop club by night.

Proof was the best man at Eminem’s wedding in January and often appeared alongside the superstar rapper at concerts and public appearances.

The two men were shot inside the C.C.C. nightclub, a small bar in a strip of businesses along Eight Mile, which divides Detroit and its northern suburbs.

In December, another member of Eminem’s inner circle — rapper Obie Trice — was shot while driving on a Detroit-area highway.