Emma finds no signs of a break-in, but hears rattling coming from the heating vent, where upon opening it, she finds a hunter's knife inside, which matches the weapon that was used in the murder.
Emma finds no signs of a break-in. Emma hears rattling. This rattling is coming from the heating vent. She is opening it. She finds a hunter's knife inside. A hunter's knife inside matches the weapon. This weapon was used in the murder.