SHELBYVILLE, Tenn. (AP) -- Tennessee police are apologizing after arresting a man for using a $50 bill they thought was fake but that turned out to be real.

Police in Shelbyville thought the bill was counterfeit after a convenience store clerk called them. The clerk said a marker used to detect false money didn't show the bill was real.

The Shelbyville Times-Gazette (http://bit.ly/JL6mJx ) reported Officer Brock Horner arrested Lorenzo Gaspar on Friday.

But a police evidence technician told the arresting officer that some old bills don't react to the markers. So police gave the money to two banks to check, and they said it was real but just very old.

Gaspar was released from jail and police apologized to him.