ANN ARBOR, Mich. -

Ann Arbor murder home Susan Ellen Wade appeared scattered and confused Monday when she was in court.

The 48-year-old woman is charged with 1st degree murder. Police investigators say she killed her father, 87-year-old Ronald Mason, this past weekend at his Ann Arbor home on Covington Drive.

Investigators said Monday that Wade waited for her father to fall asleep. She turned on several fans in the home to drown out any noise before allegedly stabbing her father 25 times. She left his bedroom and returned later and stabbed him again, making sure he was dead, investigators said.

No one could get in touch with Mason, so police went to the home.

They say Wade has a history of mental illness.

Neighbors remain in shock since police found Mason dead on Saturday.

A family member has helped police move their investigation forward.