Kartel, whose real name is Adidja Palmer, was found guilty of the August 2011 killing of associate Clive "Lizard" Williams. Kartel and the other three men -- Shawn Campbell, Kahira Jones and Andre St. John -- beat Williams to death in a dispute about two missing guns.
Williams' body was never found, but investigators discovered a text message from Kartel's phone saying Williams' body had been turned into "mincemeat," and he would never be found.
A court spokeswoman said Kartel will be eligible for parole after 35 years in prison.
The singer's lawyers said they plan to appeal the conviction.
[Wall Street Journal]