More details on Evan Ellingson's death have come to light.

The actor was found dead Nov. 5 at age 35, with authorities discovering his body in his residence, according to the San Bernardino County Sheriff's Department.

Now, a spokesperson for the department's coroner has released Ellingson's official cause of death, confirming to E! News that the former child star died of an accidental fentanyl overdose. His death has been ruled an accident.

Ellingson—whose last role was playing Kyle Harmon in CSI: Miami from 2007 to 2010—had long struggled with substance use and marked three years of sobriety before a recent relapse, according to his family. 

"He was passionate about pointing individuals to resources for help and only recently relapsed after being prescribed opioids following a dental procedure," they said in a statement to NBC News Nov. 6. "In the end, he fell in his earthly battle with addiction."

Remembering his "sweet, child-like spirit" and "smile that could light up a room," the family said Ellingson "was always thinking of others and wanted to use his own struggles with addiction to help people find hope."