Police documents say a University of Minnesota wrestling coach refused to turn over the names of student-athletes involved in the sale and use of the anti-anxiety drug Xanax.

According to a search warrant affidavit obtained Tuesday by the Minneapolis Star-Tribune, J Robinson told police in April that he had “fully taken care of” his team’s drug problem.

Campus police have been conducting a criminal investigation into a team member’s disputed allegation that Robinson attempted to cover up the widespread sale and use of Xanax by his wrestlers.

Police met with Robinson, but he refused to provide names, documents or other information pertinent to the investigation, according to the affidavit. They later executed a search warrant directed at Robinson and the wrestlers allegedly involved with the drug ring. Investigators seized computers, a DVD drive, 15 storage drives and a phone from Robinson’s office, according to the warrant.

“Robinson said that he would provide more detailed information beyond possession and use by his players if we could grant his players immunity,” university investigator Aaron Churness wrote.

Robinson’s attorney, Ryan Kaess, said the coach was trying to help his athletes by denying police access. He also called the alleged Xanax sales “ticky-tack violations.”

“I don’t believe these kids were drug dealers in the true sense of the word,” Kaess said. “They were passing them around at parties and sharing in the cost of the drugs.”