(CNN) A Columbus, Ohio, doctor was indicted on 25 counts of murder Wednesday in connection with allegations of overprescribing pain medication to patients near death.

William Husel

William Husel -- who used to work at Mount Carmel Health System -- pleaded not guilty and is being held on a $20,000 recognizance bond and a $1 million surety or appearance bond according to CNN affiliate WBNS . He is also required to surrender his passport and has a no-contact order.

The indictment documents allege that the deaths took place from February 2015 to November 2018. Each of the 25 counts could carry a penalty of 15 years to life if there is a conviction, according to a press release from the Franklin County prosecutor's office.

"Following the discovery of the actions of Dr. Husel, we notified appropriate authorities, including law enforcement. We have shared information with them and will continue to fully cooperate throughout their investigation," said Ed Lamb, president and CEO of Mount Carmel Health System, which provides care at hospitals and other health services in central Ohio.

"Mount Carmel has made and will continue to implement meaningful changes throughout our system to ensure events like these never happen again."

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