A man is "fighting for his life" after an arson attack in which a firework is believed to have been let off inside a house, police have said.
The 56-year-old victim suffered serious burns in the incident at the property in Tile Cross, Birmingham, at about 23:00 GMT on Thursday.
His partner, 50, suffered lower leg fractures when she jumped from a first-floor window to escape the blaze.
The fire in Birchtrees Drive is thought to have been started in the hallway.
The man also suffered from the effects of breathing in smoke.
Det Ch Inp Sarah Burton, of West Midlands Police, said: "The occupants of the address are in a critical condition in hospital and we are urging anyone who has information to help us trace those responsible to contact us."
The address is sealed off while forensic investigations take place.
Officers are examining CCTV footage and carrying out house-to-house inquiries.