Kathleen Peterson's Fall

Kathleen Peterson was found dead in the stairwell of her mansion. The medical examiner said it could have been caused by a fall down the stairs. Kathleen's sister candas couldn't believe what she was hearing. She says, My sister's blood is washed in pools up against the wall. It didn't look right. I still want to believe it was an accident. But all that blood up the walls, could it all be from a fall? And that's precisely what was gnawing at detective holland.