Investigators found Dumyahn's body inside her burning home in the 2300-block of Caton Farm Road Sunday morning.
An autopsy performed Monday found she was murdered. Investigators determined that the house had been set on fire to cover up the crime.
Her neighbor, Bruce Gimpel, 48, is charged with first degree murder. There is no information on a possible motive.
Dumyahn lived in the house alone since her husband died eight years ago.