A British man has died after a commercial firework was posted through his letterbox, exploding more than 200 times and sending a fire ripping through his home.
Neighbours claim Anthony Nicholls desperately tried to smash windows so that he and his partner Marie, 50, could escape the flames.
Police say the blaze started when a lit box of fireworks containing 200 tubes of explosives - normally used at outdoor public displays - was put through the door of his home in Birmingham.
The 56-year-old was rescued by firefighters who raced to the property after receiving an emergency call at 11pm last Thursday.
The former hardware store worker was rushed to hospital with 60 per cent burns and placed in an induced coma after the blaze ravaged his property.
But West Midlands Police said Nicholls never regained consciousness and detectives had now launched a murder inquiry.
His partner Marie is still being treated for fractures to her legs after jumping from a first floor window.
Neighbours on the quiet residential street reported hearing Nicholls screaming for help and trying to break the windows in a desperate bid to escape.
One elderly woman, who did not want to be named, said: "It's really shocking because this is usually a nice quiet area.
"I've been told somebody put lit fireworks through their letterbox. They were both in bed asleep and Marie jumped from the window.
"People were saying they could hear fireworks going off in the night and that they sounded very close.
"Its despicable that somebody could do such a thing. He used to work at the hardware shop over the road but gave up because of his health."
Nicholls' friend Janet Mahoney, 73, said: "He really is a nice chap - anyone who spoke to him would say the same thing. I knew him from the shop he worked in. It really is shocking and I'm so so sad for Tony - I spoke to him only three days before the fire."
Detective Inspector Paul Joyce of West Midlands Police said: "Sadly one of the victims of this fire has died and our thoughts are with his family and partner at their time of loss.
"His death means that we are now treating this as a murder enquiry and I would like to re-emphasise the need for anyone with information to call us."
He said officers were studying CCTV, but also called for members of the public who had home security camera footage and had not yet done so to share it with police.
Officers believe the firework, which gutted the home's interior, would have taken two minutes to fully discharge and are asking for help in tracing where it came from.
Joyce added: "The impact would have been terrifying for the occupants and I would urge anyone who sold or is missing a firework of this size to get in touch."