Grandmother tried to kill step-grandson three times: police

A Queensland grandmother is accused of trying to kill her 11-year-old step-grandson three times — once in a house fire and twice by suffocating him in his bed.

The 58-year-old woman from Caboolture was charged yesterday, after a long police investigation, with four counts of attempted murder, attempted arson and interfering with a corpse.

Police also continue to investigate the deaths of two other children at the family home.

Police will allege the step-grandson and another boy, aged nine, were deliberately trapped in a bedroom during a fire at a house in Morayfield, north of Brisbane, in February.

Police said the children's escape from the bedroom was intentionally impeded at a time when their grandmother was caring for them.

The boys managed to escape but one suffered burns to his lower limbs.

The woman allegedly also tried to kill the 11-year-old on two separate occasions — both times, the boy told police, he woke to his grandmother trying to smother him in his bed using a pillow and a tea towel, News Corp reports.

The grandmother reportedly denies this version of events.

She is also accused of interfering with a corpse in relation to the death of her seven-month-old grandson from the same family in September.

The baby's mother found him dead in his cot and authorities originally thought he died as a result of Sudden Infant Death Syndrome but police now suspect homicide.

Detectives are investigating that death as well as the death of a three-year-old sibling at the Morayfield home in July 2013.

The accused woman will appear via telephone link in the Maroochydore Magistrates Court tomorrow.