A former respiratory therapist was charged in the alleged murder of a patient who died 20 years ago, the New York Post reported Thursday.

Jennifer Anne Hall, a former respiratory therapist at Hedrick Medical Center in Missouri, was accused of killing Fern Franco in 2002, the New York Post reported. Franco died after she was allegedly administered a deadly dose of a muscle relaxant and morphine, also according to the outlet.

Franco was a patient at the medical center and was being treated for pneumonia at the time of her death, the outlet reported. She suffered a “ghastly death from suffocation,” according to a probable cause statement written by Brian Schmidt, an officer with the Chillicothe Police Department.

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Hall worked at the medical center for five months from 2001 to 2002 but was fired after staff learned she’d been convicted of arson for starting a fire at a previous hospital where she worked, the New York Post reported. In the five months that Hall worked at Hedrick Medical Center, the hospital saw an uptick in “code blue” incidents where patients suddenly go into cardiac arrest, also according to the outlet. Out of 18 “code blue” incidents, nine patients died, and the other nine recovered. (RELATED: Nurse Who Allegedly Set Hospital Worker On Fire Found Dead By Police)

Franco was one of the nine patients who died, the outlet reported.

Hall’s attorney Matt O’Connor said that she is “innocent” and did not have access to the supposed drugs involved in Franco’s death, according to USA Today. He also claimed she was being used as a scapegoat due to her previous arson conviction, the outlet reported. The patients who died while Hall worked at the medical center varied in age from 37 to 88.

Hall pleaded not guilty to the murder charge, KMOV reported. Her bond hearing is set for May 27, also according to the outlet.