Police are treating the death of a woman in a house fire sparked by a firework as murder, and warned the culprits that they will be caught.

Mary Fox, 59, became trapped in the house in Carpenter Court, Bodmin, Cornwall, after pushing her teenage son to safety from an upstairs window on Thursday.

Her 17-year-old son, Raum, was taken to Treliske Hospital where he was treated for smoke inhalation and later released.

Devon and Cornwall Police said a firework was found behind the front door and it had been pushed through the letterbox.

Officers leading the investigation said they would be looking at concerns that Raum was being bullied at school.

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.

"I am appealing to those people involved in this to do the decent thing and come forward to the police. If not, I am confident from what I have seen that we will be knocking on their doors shortly.

"I would ask them to come forward, and anyone who knows fact in relation to this incident, not rumour, because there is a lot of rumour going around Bodmin, to come forward and give us that information."

Mr Orpe said police were "following up leads that the family were being targeted", but said the Fox family home was not an address known to police.

"This was not an address that we were called to a number of times and we do not have any evidence within police systems to corroborate that the family were being bullied and that this was reported to the police, but that is something that we will be looking at. We will be talking to partner agencies to tell us what they know about this family."