At the 35:33 mark you see Tim Bradford searching the house from his body-cam POV. You can see the slide on his gun is locked back, meaning it is likely empty.
Nolan, after first meeting the mother of missing Olivia, stated to Harper and Perez that they checked for missing surveillance footage. There was a missing Ring Doorbell Camera on the door frame of the house and no one mentioned it yet it was clearly visible.