(AP) — A medical examiner’s investigator says Chris Kelly of the ’90s rap duo Kriss Kross died of a drug overdose.

Investigator Betty Honey of the Fulton County Medical Examiner’s office in Atlanta said Monday that a toxicology screening showed the 34-year-old Kelly had a mixture of drugs in his system when he was pronounced dead on May 1. However, Honey said she did not know which specific drugs Kelly had used.

A police report says Kelly’s mother told investigators her son used cocaine and heroin the night before he died and had a history of drug abuse.

Kelly, known as “Mac Daddy,” performed alongside Chris Smith, known as “Daddy Mac,” in the early and mid-1990s. The duo was remembered for the song “Jump” from their 1992 debut album, “Totally Krossed Out.”