MADISON, Wis. — A former Wisconsin pharmacist has pleaded guilty in federal court to charges that he tried to spoil dozens of vials of COVID-19 vaccine.

Prosecutors in January charged 46-year-old Steven Brandenburg, of Grafton, with two counts of attempting to tamper with consumer products.

Brandenburg pleaded guilty to both counts in a video conference with U.S. District Judge Brett Ludwig in Milwaukee on Tuesday. He could face up to 20 years in prison and $500,000 in fines when he's sentenced in June.

Police arrested Brandenburg on Dec. 31 as part of an investigation into how 57 vials of Moderna vaccine were left for hours outside a refrigerator.

According to court filings, Brandenburg believed the Moderna vaccine wasn't safe. There is no scientific evidence to support that contention.