The East Hampton mother accused of fatally mowing down a beloved priest was arraigned in a Riverhead court Monday. Police say 42-year-old Karen Fisher was driving drunk when she struck 79-year-old Monsignor William Costello, who was out for a walk. Authorities say Fisher's blood-alcohol reading was more than three times the legal limit at the time of her arrest. Police say Fisher was driving with a suspended license from a previous DWI arrest in April. Fisher, who pleaded not guilty to manslaughter and other charges, is due back in court on August 22. Prosecutors say in light of Fisher?s past record, they may upgrade the charges to murder.Related Information: East Hampton mom accused of fatally running down priest faces list of charges