Police have launched a murder inquiry following a fatal house fire in Cornwall. Officers have warned the culprits they will be caught after confirming the fire started as a result of a firework attack on Thursday. Mary Fox, 59, became trapped in the house in Carpenter Court, Bodmin, after pushing her teenage son to safety from an upstairs window. The 17-year-old was taken to Treliske Hospital where he was treated for smoke inhalation and later released. Speaking at a press conference at Bodmin police station, Superintendent Martin Orpe warned the people responsible for the firework attack that he was confident police would find them. "As a result of a firework that was found late yesterday behind the door within the premises, and as a result of information from the public, this is being treated as a murder investigation," he said. Officers leading the investigation said they would be looking at concerns that Mrs Fox's son, Raum, was being bullied at school.