Neil Maxwell was the only person with keys to the house in Milton Keynes where human remains were found in the loft alongside the missing teenager s backpack.
Her family said their darkest fears had come true after human remains were found on Monday in a Milton Keynes house less than half a mile from where she went missing in 2019.
Police searching for Leah Croucher in 2019 knocked on the door of the house her remains are now feared to have been found in - but instead of pursuing efforts to get inside, simply put leaflet in letterbox.