MANKATO-October 25, 2012-(KMKO)-Felony drug charges have been filed against a Mankato man.  A summons has been issued for 38-year-old Duane Scott Waltermann.  He's charged with one count of third degree sale of a narcotic for an incident in April.  Waltermann has a lengthy criminal record, with convictions for DWI, burglary and manufacturing methamphetamine.