Prince: 911 Caller May Have Big Criminal Issues

The man who called 911 in Prince's death could face criminal prosecution if he was expecting to get paid for helping the singer ... and it all comes down to the pills in his backpack.

The lawyer for Andrew Kornfeld -- whose dad runs a rehab facility in Marin County, California -- says his client is entitled to immunity from prosecution because he was acting as a Good Samaritan.

The issue -- Andrew had a synthetic opiate in his backpack, and he's not a doctor. Our sources say investigators are keenly interested in knowing why Andrew brought the pills. They are often used to wean people off drugs like Percocet -- the opiate which fueled Prince's addiction.

Andrew's attorney points to a Minnesota law that protects people who might be committing drug crimes from being prosecuted if they call 911. The idea is to give people an incentive to help others in dire need without fear of prosecution.

Here's the problem. Under the law, the person who calls 911 does NOT get immunity if they receive or expect to receive compensation for picking up the phone and making the call. It's unclear if Andrew and his dad were going to get paid, but the recovery center charges for its services, so it's a good bet they were expecting compensation.

As for the drugs in the backpack ... even if Andrew's dad prescribed the drug for Prince, our DEA sources say it's illegal for anyone to take the drugs across state lines and deliver drugs in states where the doctor is not board certified.