Editor’s Note: Danny Cevallos (@CevallosLaw) is a CNN Legal Analyst and a personal injury and criminal defense attorney practicing in Pennsylvania and the US Virgin Islands. The opinions expressed in this commentary are his.

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Pills containing deadly opioid Fentanyl, which killed Prince, were mislabeled, according to a newspaper report

Whoever provided them to the performer could face a long prison sentence, says Danny Cevallos

CNN  — 

In an important new clue, investigators probing Prince’s death have found that pills found at his compound at Paisley Park were mislabeled, according to the Minneapolis Star Tribune. The newspaper cited a source who said the pills contained fentanyl – the drug that killed the performer – but were wrongly labeled as hydrocodone. The pills may have been mislabeled by a pharmaceutical manufacturer, or the pills may have been illegally manufactured and obtained illegally.

Fentanyl is no joke; it’s incredibly dangerous. It’s a synthetically produced, Schedule II narcotic used as an analgesic and anesthetic. It is also considered by the DEA to be the most potent opioid available for use in medical treatment; 50 to 100 times more potent than morphine and 30 to 50 times more potent than heroin.

Doctors in similar criminal cases have testified that less than 10 nanograms per milliliter in the bloodstream can be fatal. The penalties under federal law are as harsh as the drug itself. Distribution of any amount over 40 grams that results in death carries a mandatory minimum sentence of 20 years.

If someone provided Prince with fentanyl, they are certainly very nervous right now; they might find themselves charged with distributing, in violation of 21 U.S.C. § 841(a). That crime is additionally enhanced by Prince’s death from the drug, covered in 21 U.S.C. § 841(b)(1)(C).

To prove this crime, the government would have to prove that someone (1) intentionally distributed fentanyl to another person, (2) knew that fentanyl was a controlled substance at the time of the distribution, and (3) Prince’s death resulted.

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Depending upon what law enforcement knows, this could be a defensible case. First, prosecutors will have to show that some defendant knowingly provided Prince with the drug. A lot of federal drug cases are the result of prolonged investigations and sting operations. Consequently, there is often surveillance video, wiretaps and undercover agents who have captured the distribution of the drugs, since the government knew in advance when the transaction was going down. By contrast, finding out who supplied Prince with prescription medication after the fact might be trickier. If there were only a few errant pills in the container, it might be hard to trace them back to a dealer.

Even if they can find the source, though, the person holding the prescription didn’t necessarily intentionally distribute anything. Even caregivers of elderly persons are not immune from the temptations of stealing prescription meds. If the fentanyl in question came from a little old lady’s script; odds are she isn’t a major player in the drug trade, but someone close to her might be.

Another possible defense is in the causation: What exactly did bring about Prince’s death? Causation is a tricky concept in the law. It historically comprises two parts: actual causation, and proximate causation.

Actual causation sounds pretty straightforward: It means that “but for” the defendant’s act, the event would not have occurred.

But drug overdoses can create a “causation” problem. If that first act combines with other factors to produce a death, and the other factors alone would not have done so? If you are stung by a swarm of bees and die, is any individual bee by itself a cause of death? The Supreme Court recently addressed this exact issue of the “straw that breaks the camel’s back” in the context of prosecution for a drug death.

In that case, the court held that if a drug user dies after taking in multiple substances, the person who supplied one of those substances (like the fentanyl) can only get hit with that enhanced 20 year sentence if that one drug was the actual cause of the death.

The new rule is this: It is not enough if the one drug just played a role in the result, if it did not itself cause that outcome. Defendants now have an incentive to challenge the prosecution’s theory of the cause of death.

Federal appellate courts in the jurisdiction including Minnesota have suggested the law is a “strict liability” statute for death arising from the intentional distribution of a lethal drug: If the drug caused the death, guilt is automatic, irrespective of foreseeability.

As you can imagine, drug cases often deal with street level dealers as defendants. In the Prince case, the drugs might have been mislabeled by a legitimate corporation, or illegally manufactured.

If a corporation mislabeled or manufactured the pills, the Federal Food Drug and Cosmetic Act outlaws engaging in interstate commerce with adulterated or misbranded drugs. Penalties include imprisonment and sanctions like seizures, injunctions and fines.

Illegal manufacture of drugs like fentanyl is a major problem, according to the DEA. Hundreds of thousands of counterfeit prescription pills, many containing deadly amounts of fentanyl and fentanyl-related compounds, have been introduced into the drug market, according to a July report. The DEA reports that overseas labs in China are mass-producing the drug and related compounds and marketing them to drug trafficking groups in Mexico, Canada and the United States. In addition, law enforcement nationwide report higher fentanyl overdose deaths than at any other time since the drug was developed in 1959.

Still, little is known at present about the origin of these pills. Somewhere out there, anyone who might have been responsible for Prince obtaining these pills has reason to be concerned. Merely providing the pills, under federal law, is possibly enough to be guilty of a crime with a 20 year mandatory minimum.

It sends a sobering message to those who want so badly to party with or be close to celebrities: Drug overdoses are frequently the fault of choices primarily made by the victim. However, when the world is deprived of a great artist, the people want someone else to be held responsible. And if the federal government decides someone else is responsible, that person faces decades in jail from a single sale.