Grieving mum believes 'third party' was involved in death of her 19-year-old son

The heartbroken mother of a Scottish teenager, who was missing for a month, believes a 'third party' was involved in her son's death. Nineteen-year-old Cole Cooper vanished on May 9, sparking a four-week major search which involved helicopters, divers and specialist teams to track him down. He was last spotted on CCTV five days before, trying to enter his father's home after a house party.