Grandmother beat elderly man unconscious and set him alight

Justice Ellis said it was not clear whether the head injury, the fire or both had killed the victim. Photo / Thinkstock

An Auckland grandmother who beat a 77-year-old man unconscious before setting him on fire will spend at least the next 15 years in prison.

The 48-year-old woman, whose name is suppressed, previously admitted the murder of Peter Lance Dixon, who was found dead in his South Auckland home after a fire in February 2012.

The High Court at Auckland yesterday heard the horrifying details of the killing, which Crown prosecutor Warren Cathcart called "calculated and callous in the extreme".

The woman, who whimpered throughout, was jailed for life and Justice Rebecca Ellis imposed a minimum non-parole period of 15 years.

Emergency services were called to a fire at Mr Dixon's home on the morning of February 27 and found him dead in his bedroom.

The court heard how the grandmother beat the man around the head and neck with a heavy object before setting his legs alight.

"This is a 77-year-old man who has been incapacitated by a blow to the head and neck. He was vulnerable and she set him alight," Mr Cathcart said. "This has been carried out by a calculated mind that contains no pangs of conscience."

Justice Ellis said it was not clear whether the head injury, the fire or both had killed the victim.

Only hours earlier, the offender had set a tissue box alight and placed it underneath Mr Dixon's bed. He woke up and put out the fire. She later deactivated smoke alarms and waited for the fire to take hold before she called emergency services.

The judge said the woman's actions could be partially explained by a history of sexual abuse and subsequent mental health issues; however, the victim was not the perpetrator of those crimes.

The woman was also sentenced on four counts of arson, one of attempted arson and four charges of theft by a person in a special relationship amounting to $12,500. The charges stemmed from offending at her workplace before the murder.