Detectives are investigating how a four-year-old boy was stabbed to death at a flat in south London. Officers who were called to the flat in Southwark Monday evening found the child suffering from stab wounds. He was pronounced dead at the scene. A man and a woman also discovered at the flat, and thought to be his parents, were treated in hospital for stab wounds. The woman, 28, had suffered a neck wound, and the man, 31, was described as having serious wounds. A 17-month-old girl also found at the address was unhurt. “At this stage, officers are looking into all the circumstances surrounding the child's death. There have been no arrests and they are not looking for anyone else in connection with the incident,” the Metropolitan police said in a statement.