The hip-hop world is still mourning the death on Friday of Three 6 Mafia member Ricky "Lord Infamous" Dunigan, who passed unexpectedly at his mother's home in Memphis at the age of 40.

While an official cause of death has not yet been revealed, Infamous' half-brother and Mafia co-founder, DJ Paul, told HipHopDX that he believes a heart condition may have played a role.

"He had a heart attack in his sleep," Paul told the site. "His mother found him dead this morning. He had been dead, the doctors say, for about five hours. And she came home, he was sitting at the kitchen table with his head down on his arms. He had told his girlfriend that he was sleeping and he wanted to go to sleep. His girlfriend left and was like, 'You going to be fine?' And he was like, 'Yeah, I'm going to be good.' And she was like, 'You sure?' and he was like, 'Yeah, yeah, I'm positive, I just want to get some sleep.' So he laid his head in his arms at the kitchen table and he went to sleep and then when his momma came home, he was sitting at the kitchen table passed away.

Infamous suffered a heart attack and stroke back in 2010, but Paul said he wasn't sure if the previous heart issues played a role in Infamous' death. "We don't know yet [if the two incidents were related]," he said. "It probably did. A lot of times people have heart attacks and a lot of people survive heart attacks and usually when they have that second, third one, it's pretty much over with."