The woman had called 911 around 5 a.m. summoning officers for medical assistance to her mobile home in the 3300 block of 228th Street SE.
Langford said the woman met officers outside her front door and made some "concerning statements." Officers went inside to find her 80-year-old mother suffering from severe traumatic injuries.
Medics arrived on scene but the victim was pronounced dead shortly thereafter, Langford said. The daughter was then taken into custody.
Investigators were getting a search warrant to process the crime scene.
The victim's name has not been released.