Officers investigating the death of a man killed by a firework have released images of three women they would like to speak to.
Anthony Nicholls, 56, died in hospital after an industrial sized firework gutted his Birmingham home last month.
His partner has been left with serious injuries after jumping out of a window to escape.
Police are asking the women to make contact as they may have "vital information".
A £10,000 reward has been offered to help find the attackers.
The force said officers have looked at CCTV of the surrounding area prior to the incident, in Birchtrees Drive, Tile Cross, and are asking the women to get in touch.
Det Insp Paul Joyce, from the force's homicide team, said: "We believe that someone knows who committed this dreadful act which has devastated Mr Nicholls' family.
"We have not let up in our investigation to trace the culprits and I would urge these women to come forward, or anyone who knows them should contact my team."
Three men and one woman have been arrested on suspicion of conspiracy to commit murder and are on police bail.