The 1996 unsolved murder of Tupac Shakur is examined in a segment of National Geographic Channel's upcoming documentary, 'The '90s: The Last Great Decade?'

In a brief clip, which premiered exclusively on Rolling Stone, Outlawz member Malcolm Greenridge and '2 of Amerikaz Most Wanted' video director Gobi Rahimi discuss the last six days the late rapper was in the hospital before he ultimately died from gunshot wounds.

The pair also talk about why Shakur's murder remains unsolved for almost 20 years.

“Law enforcement around the country weren’t big Tupac fans," says Greenridge. "I’m absolutely positive they know what happened. This is America. We found Bin Laden.”

But veteran talk show host Arsenio Hall believes race is one of the main factors as to why Shakur's murder hasn't been solved.

“I believe that if Justin Bieber had gotten shot in Tupac’s car, we’d know more,” he said.

National Geographic's 'The '90s: The Last Great Decade?' is a six-hour documentary that will air on July 6 through 8 at 9PM ET. Among the panel of guests talking about events from the decade include Ice Cube, Vanilla Ice, Courtney Love and veteran journalist Brian Williams.