Lord Infamous*Ricky “Lord Infamous” Dunigan, a co-founding member of the Memphis, Tenn.-based rap group Three 6 Mafia has died. He was 40.

News of Infamous’ death was confirmed by his half brother/fellow Three 6 member DJ Paul, who told Rolling Stone that Infamous died in his sleep of a heart attack Friday night at his mother’s house in Memphis.

“He was at home sitting at the table and he just lay his head down and he just left us,” Paul said.

Lord Infamous began his hip-hop career alongside DJ Paul in Memphis in the early 1990’s. The pair, along with Juicy J, formed Three 6 Mafia in 1991 and released their debut album, Mystic Stylez four years later. Three 6 gained worldwide exposure in 2005 after becoming the first rap group to win a Best Original Song Oscar for their song “It’s Hard Out Here for a Pimp.” The track was featured in the film “Hustle and Flow.”

Earlier this year, most of the Three 6 Mafia’s members reformed under the name Da Mafia 6ix and released a mixtape called “6ix Commandments.”

Prior to his death, Lord Infamous had been working with the group on a new album, which is set for release in March 2014, DJ Paul said. Although he had not been ill recently, Paul also said that Infamous suffered a stroke and heart attach in 2010.

In addition to Da Mafia 6ix’s album, Infamous was preparing for the re-release of his old mixtape series, which is also due out in March.

“He was a legend in the game, truly ahead of his time,” DJ Paul shared with Rolling Stone. “He was such a great lyricist and he always came with these different styles in his rap and his flow.”

“Lord Infamous was the kind of person that never cared about having a lot of money or this or that,” continued the rapper, who mentioned how his half-brother was known for his generosity and loved by everybody. “He just liked to make music, he liked to rap, and he liked to make people happy.”