HELENA, Mont. (AP) — State regulators have indefinitely suspended the license of a southwestern Montana physician for continuing to practice medicine without meeting the requirements of a probationary license.

Chris Christensen's license was suspended in April 2014 after an investigation found he over-prescribed narcotic pain medication to patients, including two who died of drug overdoses.

The state Board of Medical Examiners issued Christensen a probationary license in May 2015 under several conditions, including that he find another doctor to supervise him.

In August, Christensen was charged with 400 felonies, including two counts of negligent homicide for the overdose deaths. He has pleaded not guilty.

The board held an emergency meeting Tuesday and suspended Christensen's license again after learning he was refilling patients' prescriptions for non-narcotic medication without seeing them and without another doctor's supervision.