(CNN) -- Ricky Dunigan, better known as Lord Infamous, a founding member of the Oscar-winning rap group Three 6 Mafia, died of a heart attack last week, according to a release from Black Rain Entertainment.
Dunigan, 40, died Friday.
"Dunigan's family is grateful for all the condolences and prayers, and would like to request privacy in their time of grief," the statement said.
Lord Infamous left the group in 2006, the year Three 6 Mafia surprisingly won an Academy Award for best original song with "It's Hard Out Here For a Pimp," from the movie "Hustle & Flow." Billboard reported he was forced to leave, having spent time locked up.
That year, Dunigan and Il Tone, a longtime friend, founded the music company Black Rain Entertainment, and Lord Infamous soon began a solo career.
Earlier this year, he rejoined his old band mates to form Da Mafia 6ix, according to Rolling Stone magazine.
One of his fellow rappers, DJ Paul, who was with him at his mother's house in Memphis, Tennessee, when Lord Infamous died, said, "He was at home sitting at the table and he just lay his head down and he just left us."
The group was planning to release an album next March.
"Lord Infamous was the kind of person that never cared about having a lot of money or this or that," DJ Paul told Rolling Stone. "He just liked to make music, he liked to rap, and he liked to make people happy."
Juicy J, another Three 6 Mafia member, thanked fans for their condolences on Twitter: "Thx you for your prayers, I'm very hurt, can't believe it's true," he wrote to his 1.4 million followers.
Rolling Stone reported that Lord Infamous had a heart attack and stroke in 2010, but had not been sick recently.