When you consider the strength of the killer,Mickey had to be the Killer.Which means that Mrs. Loomis was upstairs making noises and the calls.This gave Mickey enough time to sneak in.Then he stabbed chased her up the stairs,threw her through a glass door,stabbed her twice in the back,and threw her off the building.This would explain how Mickey got the tape of Cici coming outside and how Mrs.Loomis was at the scene right away,posing as Debbie Salt.
