Police say an 18-year-old woman set ablaze in a suspected satanic ritual has died.

Kirsty Theologo died Friday at the hospital where she had been in a coma with third and fourth degree burns to her body from the waist up, including serious burns to her lungs.

Spokeswoman Lorraine Van Emerik said one of the charges against four young men accused in the case will be changed from attempted murder to murder.

Court records say that Theologo and a 16-year-old friend were among eight young people who went behind some rocks at a suburban swimming pool a week ago. The two girls were then tied up, doused in petrol and a match was thrown at them.

The 16-year-old was not as badly burned as Theologo and survived.