A six-year-old girl has died in hospital after two men set fire to a house containing five children and their mother.
The family were forced to jump from a first floor window
Police said the men forced their way into the property in Bayswater Road, in the Perry Barr area of Birmingham, after a disturbance on Friday evening.
Detectives are treating the girl's death as murder and linking the fire with an earlier incident at the house.
The remaining children and their mother were treated in hospital.
The children, who are all Asian, are aged between five and their late teens.
Ch Supt Stephen Dugmore, of West Midlands Police, appealed for members of the Asian community to contact them with information about the incident which he described as "heartless".
He said the two men, wearing dark clothes, burst into the house at 2345 GMT on Friday and threw a substance, believed to be petrol, into the property.
The family ran upstairs and had to jump to safety from an upstairs window, but the six-year-old became trapped inside the house and had to be rescued.
The men, thought to be accompanied by others, then fled.
The family's car, a Vauxhall Astra, which was parked outside the house, was also damaged.
West Midlands Police said the five-year-old was taken to Birmingham Children's Hospital, but died at about 1925 GMT.
Ch Supt Dugmore said: "We believe there is history of some kind behind what happened last night.
"We know there was a disturbance outside the house the night before and really, I would ask people if they know anything about the earlier disturbance or last night to get in touch.
"It's a heartless crime."
Shocked neighbours said the family had been living at the address for about two years.
House-to-house inquiries are continuing and a police incident room has been set up.