OKLAHOMA CITY (AP) — A former Oklahoma doctor has been convicted of second-degree murder in the opioid overdose death of a patient, according to state Attorney General Mike Hunter.

Former Midwest City Dr. Regan Nichols was convicted Friday on one of five counts of second-degree murder for the deaths of five patients between 2010 and 2013.

Nichols was acquitted on the remaining four counts.

"The facts and the evidence in this case were clear – through her reckless overprescribing, Regan Nichols put her patients in danger, which led to tragic deaths," Hunter said.

Nichols prescribed more than 1,800 opioid pills to the five people who died during the same months as their deaths, according to investigators.

Defense attorney Tommy Adler told The Oklahoman that the guilty verdict will be appealed.

"We're very surprised by the one conviction," Adler said. "We believe (the jurors) worked hard."

Hunter successfully sued pharmaceutical company Johnson & Johnson for a misleading marketing campaign that overstated how effective the drugs were for treating chronic pain and understated the risk of addiction.

The case has been appealed to the state Supreme Court.

Hunter also reached pretrial settlements with other drugmakers and has filed a lawsuit against three opioid distributors.