Police were called to a home in the 17300 block of Woodcrest Drive at 11:30 a.m. on Tuesday. When they arrived they discovered a badly beaten 91-year-old man inside the home.
That man, who has not been identified, was taken to Harborview Medical Center with life threatening injuries, according to police.
A 52-year-old woman who also lives at the house was arrested on suspicion of second degree attempted murder. Police have not said how the woman is related to the beating victim.
The investigation is ongoing.