ST. LOUIS COUNTY, Mo. (KMOX) -  A bizarre story out of south St. Louis County, where police say a woman beat her grandmother because she believed the 92-year-old was possessed by a demon.

37-year-old Rachel Armstrong now faces first-degree elderly abuse charges.

According to a police report, Armstrong was at her home near Sappington when she threw her grandmother to the ground and stomped on her, breaking both of her arms and eight ribs during the November 12th incident.

Armstrong reportedly explained that her grandmother was a demon and she was attempting to beat it out of her before putting the elderly woman to bed.

She’s jailed on $75,000 bond and will undergo a series of psychological tests.