The Federal Drug Enforcement Administration is now involved in the death investigation of Prince, and our law enforcement sources say drugs are the focal point of the criminal probe.

Our sources say the DEA and the Minnesota Attorney General are looking into the various prescriptions that were written for Prince, and the focus is opiates. Prince had a life-threatening Percocet addiction and authorities believe opiates will likely be either the sole or at least a significant factor in his death.

Our sources say the investigation is sweeping ... doctors and pharmacies involved in prescribing and filling meds for Prince are targeted, but possible enablers are also in the crosshairs.

Our sources now say the toxicology report may still be weeks away, although it was initially set to be released 2 weeks after the autopsy.  

We know at least one doctor was a friend of the singer, but we're told the investigation is much broader.