Answer:
Most likely, the victim could have been followed home from the grocery store. or the victim was murdered by a neighborhood thief who snuck in to get the drop on her. or a recent lover or family member who was seeking revenge. the door indicates that there was forced entry, so she had already been home from the store, but not for too long cause she had yet to put the groceries away. the killer wasn't worried about leaving the weapon, so it's either a lousy killer or a killer who wants to be caught. we will rule out the possibility of a robbery. She probably knew her killer given the facts that we have.