Police investigating the nightclub shooting death of rapper Proof questioned a bouncer who is a cousin of a man critically injured in the gunfire.

Police also said Wednesday it was Proof, 32, who fired the first bullet at the CCC nightclub, hitting Keith Bender in the head. Bender remained in critical condition early Thursday at St. John Hospital, spokeswoman Wende Berry said.

The shootout erupted before dawn Tuesday, more than two hours after the nightclub was required to close for the night. Investigators believe Proof was shot after he pistol-whipped and shot Bender at the club on Eight Mile Road, which was memorialized in the 2002 film starring rap superstar Eminem, Proof's close friend.

Bender's cousin Mario Ethridge, 28, spoke to investigators Wednesday, the Detroit Free Press reported.

"He came in because the Detroit Police Department asked him to," his attorney Randall Upshaw told WXYZ-TV. "Does that sound like a murderer?"

Upshaw declined to say whether his client shot Proof but said whoever did acted in self-defense.

"The understanding of every witness we've spoken to is that Proof pulled out a weapon," Upshaw said. "Proof shot Keith in the face, and Keith was unarmed."

Proof's shooter will not be charged if that person was protecting himself or someone else, police Sgt. Eren Stephens said.

Bender's mother, Leona Bender, said Thursday that she and her family were just "trying to cope."

Proof whose real name was Deshaun Holton, was shot three times in the head and chest, according to the Wayne County medical examiner's office. He was taken to a nearby outpatient treatment center, where he was pronounced dead.

He was a member of the rap group D12 and was the best man in Eminem's January wedding. Seldom was Eminem seen in public without him.