Kirstie Foster is confirmed as the third, body found in the mansion.
LONDON, England (CNN) -- DNA analysis has confirmed that a third body found in the burnt-out mansion of millionaire Christopher Foster was that of his 15-year-old daughter, police said Thursday.
British police believe Foster killed his wife and his daughter before setting fire to their home and taking his own life.
They had earlier used dental records to determine that two of the three bodies found in the burnt-out remains of the property 280 km (175 miles) northwest of London were that of Foster and his wife, Jill.
Police had been working on the theory that the third body was that of 15-year-old Kirstie.
The test results, which came back Wednesday, positively identified the girl.
The sprawling house was destroyed August 26 by a fierce blaze, which left the remains too unstable for officers to enter for several days.
On August 29, detectives discovered two bodies inside, and two days later the investigation became a murder inquiry when forensics showed Jill Foster, 49, had been shot in the head.
Police found Kirstie Foster's body in the property near Maesbrook, Shropshire, two days later.
Authorities have not yet determined the cause of death of Christopher Foster and his daughter.
Three horses and four dogs were also found dead at the estate. Police said Sunday the animals had been shot.