The 1997 murder of Christopher "Biggie" Wallace was never solved. And for the past 20 years, there have been all kinds of theories about who killed the legendary rapper, and why.

Over the weekend, Diddy's former bodyguard Gene Deal just made a stunning new claim. In a new video, Gene suggests that Bad Boy artist Mase may have had some involvement in Biggie's killing.

Mase called into Gene's Youtube show, and called him a liar. According to Mase, Gene used to be an upstanding guy - but now he's lying for ratings and Youtube clicks.

Gene fought back - confronting Mase about what he calls suspicious behavior. Gene asked Mase, why he didn't go to the party the night Biggie was killed. Mase told him that he was in a hotel room with R&B singer Brandy. 

But Gene contradicted the rapper. He claims that Mase told him that Brandy wanted to go to the party, but it was Mase who didn't wanna go. 

Mase and Brandy were dating at the time.

The discussion got heated, and Mase eventually hung up the phone.

Here's the video: