A former employee of a Massachusetts skilled nursing facility pleaded guilty on Tuesday to charges that she stole morphine from the facility and replaced some of it with saline.

Lea Roberge, a former registered nurse at Holy Trinity Orthodox Nursing Rehabilitation Center in Worcester, MA, was fired in April 2015 for violating a facility protocol that required staff members to have a witness with them when opening an emergency narcotic kit.

Roberge’s firing came after other employees found the rubber stoppers on several vials of morphine sulfate injection had been punctured. A bottle of morphine sulfate solution also revealed evidence of tampering. Tests showed that some of the drug had been removed from each vial, according to local reports.

Roberge admitted to tampering with the vials and replacing some of the missing morphine with saline. She pleaded guilty to two counts of tampering with a consumer product.

Roberge told investigators that she did not take the morphine herself, but gave it to someone who was “sick” with a drug addiction. She also noted that she had become dependent on pain medication after being in a car accident, so she “knew what it was like to be sick in that way,” according to court records.

McKnight’s requests for comment from Holy Trinity were not returned by press time Wednesday.

Roberge’s sentencing is set for April 5; if convicted she faces up to 10 years in prison for each count.