After investigation a medical examiner has ruled that underground rapper Mikey “Eyedea” Larsen died of an accidental overdose.

According to Minnesota’s Star Tribute the exact cause of death was opiate toxicity, but it is unknown which specific drugs he was using. Following his death last October, his mother, Kathy Averill, said he did not have a problem with addiction.

Eyedea made a name for himself by winning a handful of rap battles, including 1999’s Scribble Jam, and 2000’s Rocksteady Anniversary and the HBO televised, Blaze-Battle World Championships, among others. He soon linked up with DJ Abilities and the duo formed a friendship with fellow MN outfit Atmosphere, signing to their label, Rhymesayers Entertainment. Dubbed Eyedea & Abilities, the group released three solo discs on the imprint, including 2001’s First Born, 2004’s self-titled LP and last year’s By the Throat. As a solo artist, Eyedea also recorded 2002’s The Many Faces of Oliver Hart, which also showcased his talents as a producer. —Elan Mancini