Officials in Georgia say at least a dozen people were hospitalized over two days in the state after ingesting an unidentified street drug. Four deaths have been linked to the drug.

CNN reports some patients said they took a yellow pill they thought was the prescription painkiller Percocet.

According to a news release from the Sheriff’s Office of Bibb County, Georgia, the counterfeit pills have the numbers 10/325 on one side and the word PERCOCET in all capital letters on the opposite side. “On the counterfeit pills the word PERCOCET is not stamped as deep as the manufacturer typically does on their pills. Also on the counterfeit pills, the imprint of the name is also at an angle.”