I think what LE meant there was no weapon found inside of the home that would match the gunshot wounds of both victims. LE is very good at looking at the gunshot wounds and knowing the possible caliber of guns that would have made those particular entrance wounds. Plus the ME would come to the scene and tell them the type of caliber to be looking for. They know the caliber and imo it was not one owned by her dad. They will know if they find one tossed it belongs to the killer. Imo I highly doubt he tossed it though. He thinks he may need it in the future.