Hawaii crime boss dies of overdose in federal custody: medical examiner

Michael Miske, 50, died of "toxicity of fentanyl and para-fluorofentanyl," the medical examiner's office said in a statement obtained by the Associated Press. The death appears to have been accidental, but the case is still under investigation, the news agency added, and an autopsy report will likely take at least another 30 days. 

Miske was found unresponsive at the Honolulu Federal Detention Center on Dec. 1. Efforts by staff and emergency medical responders failed to save him, the Bureau of Prisons said, according to the AP.

It is unclear how the mastermind of the "Miske Enterprise" from the late 1990s until his July 2020 arrest in the kidnapping and murder of 21-year-old Jonathan Fraser came into possession of fentanyl or para-fluorofentanyl, a synthetic opioid that appears in illicit drugs and is more potent than fentanyl.

Fraser was best friends with Miske's late son, Caleb Miske, Bloomberg reported. The pair, who loved cars and racing, were in a high-speed crash together in November 2015 - Caleb Miske succumbed to his injuries. Although a police report indicated that Caleb had been driving, according to the outlet, Miske insisted that Fraser was responsible for the death of his only son. 

Miske's conviction entitled the government to take control of up to $28 million in assets, including boats, houses and artwork.

The Federal Bureau of Prisons did not immediately respond to a Fox News Digital request for comment. 

Fox News' Christina Coulter and the Associated Press contributed to this report.