Pills that had been found in addition to marijuana in the dormitory of the Nihon University American football team contained traces of stimulants, prompting the Tokyo Metropolitan Police to raid the dorm on Thursday on suspicion of a violation of the Cannabis Control Law and the Stimulants Control Law.

Sources close to the investigation said Friday that the drugs were stored in a small bag inside one player’s locker.

Police are planning to conduct a further investigation into the 21-year-old male football player who is suspected of possessing them. They are attempting to trace how he might have acquired the pills.