Officials had previously said that 43-year-old Asabech Abayneh's death was a homicide but had not said how she died. Abayneh was found dead Friday.
Police said the homicide is Alexandria's third of 2014.
The normally quite city had been dealing with a string of unsolved killings, most recently the fatal shooting of a music teacher inside her home earlier this year.
Police have said that former Alexandria resident Charles Severance is the focus of their investigation into that and two other slayings.
Severance has not been charged but is in custody in Loudoun County on an unrelated weapons charge.