Rapper Chris Kelly, who was one half of the popular ’90s group Kriss Kross, died in May under mysterious circumstances; at the time, police said they believed it to be drug related, but didn’t release many details. Now, the coroner’s report has come back, and it looks like his death has been ruled an overdose.

Kelly reportedly had a mixture of drugs in his system when he died, including heroin and cocaine. His mother told police he had a history of drug abuse and had been using the night he passed away. She was the first to issue a statement about his death, saying:

“It is with deep sadness that we announce that our beloved Chris Kelly has passed away on May 1. To millions of fans worldwide, he was the trendsetting, backwards pants-wearing one-half of Kris Kross who loved making music. But to us, he was just Chris – the kind, generous and fun-loving life of the party. Though he was only with us a short time, we feel blessed to have been able to share some incredible moments with him. His legacy will live on through his music, and we will forever love him.”

Kelly and friend Chris Smith were discovered at an Atlanta mall as teenagers by producer Jermaine Dupri, and soon shot to stardom with their debut album “Totally Krossed Out”. Their style of dress–wearing clothes backwards and sagging their jeans–became enormously popular with middle-school and high school-aged kids, and the duo enjoyed success through most of the ’90s. Although they’d moved on with their careers separately as adults, they reunited earlier this year to perform at the So-So Def 20th Anniversary Concert.