COLUMBIA, S.C. – A South Carolina sheriff said Monday he was not going to charge swimmer Michael Phelps after a photo of the 14-time Olympic gold medalist showed him smoking from a marijuana pipe.

Richland County Sheriff Leon Lott said during a news conference that he didn’t have enough physical evidence to charge Phelps, but he defended his investigation.

“Michael Phelps is truly an American hero … but even with his star status, he is still obligated to obey the laws of our state,” Lott said.

Phelps released a statement after the sheriff’s decision.

“I’m glad this matter is put to rest. But there are also some important lessons that I’ve learned,” Phelps said in the statement. “For me, it’s all about recognizing that I used bad judgment and it’s a mistake I won’t make again. For young people especially – be careful about the decisions you make. One bad decision can really hurt you and the people you care about. I really appreciate the support my family and fans have shown me and now. I will move forward and dive back into the pool, having put this whole thing behind me.”

The photo showed Phelps smoking from a marijuana pipe at a party in November when he visited the University of South Carolina. Lott said he seized the marijuana pipe that was in the photo but couldn’t prove Phelps had smoked from it.

“We had a photo and him saying he was sorry for inappropriate behavior. He never said, ‘I smoked marijuana.’ We didn’t have physical evidence,” Lott said.

USA Swimming suspended Phelps for three months in the wake of the photo, and Kellogg Co. said it would not renew its endorsement deal with him.

The photo surfaced in a British newspaper, News of the World, on Feb. 1. Phelps did not dispute its authenticity.

News of the World said the picture was taken during a party while Phelps was visiting the university.

The party occurred nearly three months after the Olympics and his actions should have no impact on the eight golds he won at Beijing.