The investigation into a Danville doctor whose medical license was suspended last week continues after authorities say 12 of his patients died of overdoses.

This has promoted other law enforcement agencies to review their overdose cases, to figure out if they were also patients of Dr. Melborne Williams a licensed psychiatrist.

After learning of Williams suspension, Lincoln County Coroner Farris Marcum tells 27 NEWSFIRST he started reviewing several drug overdose cases in his county, including the recent death of Crystal Hager.

"To my understanding she had been in the hospital prior to her death, she had been a patient of Dr. Williams," Marcum said.

Last week, the Medical Licensure Board ordered an emergency suspension of Williams' license after Clay County Sheriff Kevin Johnson launched an investigation into a dozen deaths in his community alone, he says, were all patients of Williams and were being prescribed excessive amounts of drugs like Xanax regardless of their diagnosis.

"Usually when they died, there was a two or three day period of time where they had went and seen Dr. Williams," Sheriff Johnson said.

Williams was unavailable for comment when we went to his Danville office. His attorney James E. Smith of Louisville told the Herald-Leader quote "We are confident that once the allegations are fully analyzed that Dr. Williams will be fully vindicated."

Marcum says he's not on a witch hunt. He's doing due diligence, like he would anytime a red flag is raised.

"We'll look at the total numbers and if it's something that stands out to us then, ya know, of course we would share that with the local authorities."

At this time Dr. Williams has not been criminally charged, but authorities tell WKYT that could change as they further their investigation.

According to the Medical Licensure Board Dr. Williams was the number one prescriber of Xanax in Kentucky from April 2011 to March of this year.