It happened about 11:10 a.m. Saturday at TD Bank at 300 Delaware Avenue. Officers say a man entered the bank and demanded money from a teller.
Police say the man did not see Sgt. Fray Lynch, who was working an extra duty security assignment at the bank in full uniform. Officers say Lynch radioed for assistance and took a man in custody after a short struggle.
Thirty-five-year-old Melvin Miranda of New Castle has been charged with robbery and resisting arrest.
