BOSTON (AP) -- Federal prosecutors plan to retry a former Massachusetts doctor and nurse practitioner charged with conspiracy and drug trafficking for allegedly distributing methadone, oxycodone and fentanyl without legitimate medical reasons.

U.S. District Judge Patti Saris declared a mistrial in the case Monday after jurors said they were hopelessly deadlocked on the charges against Dr. Joseph Zolot and nurse practitioner Lisa Pliner.

U.S. Attorney Carmen Ortiz said in a statement that she intends to retry Zolot and Pliner.

During the trial, prosecutors said Zolot and Pliner ignored evidence that some of their patients were misusing, abusing and even selling drugs they prescribed. Six patients died.

The defense described them as caring health care providers who wrote each prescription in good faith.