MIAMI (AP) — An autopsy has confirmed that a 10-year-old Florida boy is among the state's youngest victims of the opioid crisis.

A report from the Miami-Dade Medical Examiner confirms preliminary findings that Alton Banks died with fentanyl and heroin in his system. The autopsy lists the boy's June 23 death as an accidental drug overdose, though it's not clear how the deadly opioids got into his system.

Heroin mixed with fentanyl is a common street drug combination.

Miami police have said Alton apparently encountered the drug during a one-hour period after he left a pool in the Overtown neighborhood and got home. Alton began vomiting at home, lost consciousness and later died at a hospital.

Investigators didn't find any evidence that the contact occurred at home. No one has been charged in his death.