Forensic pathologist Michael Baden said Wednesday that he performed the second autopsy at the family's request. He says he's awaiting test results.
Baden is paid to give independent opinions on deaths. He has testified in several high-profile cases including the O.J. Simpson trial.
Lighty was found dead in his Bronx apartment with a gunshot wound to the head. The medical examiner ruled it a suicide. But his brother Dave Lighty has indicated that he isn't sure his brother took his own life.
Hip-hop stars including LL Cool J, 50 Cent and Sean "Diddy" Combs attended Lighty's funeral in Manhattan on Wednesday.