A man has volunteered for questioning by police in Detroit over the death of a member of Eminem's rap collective D12 in a nightclub shooting.
Rapper Proof's real name was Deshaun Holton
The man spoke to officers investigating the death of Proof, real name Deshaun Holton, who was shot at a club on the famous Eight Mile Road.
The police said they believed Proof, the best man at Eminem's wedding, fired the first shot in the exchange.
A second man shot in the incident is in a critical condition in hospital.
Keith Bender, 28, is being treated at a hospital in Detroit, following the early hours shooting on Tuesday.
The Wayne County medical examiner's office, which examined Proof's body, said he was shot three times in the head and chest.
The rapper was credited with the idea of forming D12 with a group of friends from Detroit.
Proof, second left, was a founder member of D12
Despite Eminem's huge solo success, he continued to record with the group, which released the albums D12 World and Devil's Night.
The group scored a number two hit in the UK with Purple Hills in 2001 and My Band in 2004.
Proof also made an appearance in the critically acclaimed film 8 Mile and was credited on the award-winning soundtrack.
His best man duties came at Eminem's second wedding to Kim Mathers in January. The pair have since announced plans to divorce again.