MADISON, Wis. — Authorities arrested a suburban Milwaukee pharmacist Thursday suspected of deliberately ruining hundreds of doses of coronavirus vaccine by removing it from refrigeration for two nights.

The Grafton Police Department said the former Advocate Aurora Health pharmacist was arrested on suspicion of reckless endangerment, adulterating a prescription drug and criminal damage to property. The department said in a news release that he was in jail. Police did not identify the pharmacist, saying he has not yet been formally charged.

Jeff Bahr, Advocate Aurora Health Care chief medical group officer, told reporters during a teleconference Thursday afternoon the pharmacist deliberately removed 57 vials of the Moderna vaccine from refrigeration overnight on Dec. 24 into Dec. 25, returned them, then left them out again on the night of Dec. 25 into Saturday.

A pharmacy technician discovered the vials outside the refrigerator Saturday morning. Workers used the vaccine to inoculate 57 people. Bahr said their doses were ineffective.

The recipients shouldn’t be in any danger, Bahr said, but the system is monitoring their conditions.

The pharmacist intentionally removed the vaccine from refrigeration, Bahr said, but he declined to comment on the individual’s motive, saying the person has been fired and police are investigating. He did not identify the pharmacist and stressed the facility’s security protocols are sound.

“This was a situation involving a bad actor, as opposed to a bad process,” he said.

Police in Grafton, about 20 miles north of Milwaukee, said in a statement that the department, FBI and Food and Drug Administration are “actively” investigating.