It could have been a person or people interested in Suzie and Stacy. They could have been followed home or never made it inside the Delmar house. Graduation makes things unpredictable. Plans change, parties get broken up by cops, and you have out of town relatives.IMHO I believe this was a well planned out attack and they was just waiting for the right time to do it. It’s just unfortunate Stacey was in the wrong place and the wrong time. I think they (perps) saw the opportunity or was ordered early that morning to go to Delmar and carry out the crime. I may be wrong but I certainly think it’s possible to have happened this way.