"The fire started in the kitchen at the rear and spread from there to involve the entire house, including obviously the bedroom where the bodies of the couple were found," said specialist fire investigator Derek Goodwin.
The couple were found in their beds.
"The oven in the kitchen had a gas cook top and one of the elements of the cook top had been left on, with a pot on it."
Mr Goodwin said the alarm was raised by a passerby who saw a lot of smoke around the house.
"The call came in at 3.15am and the Tolaga Bay volunteer fire brigade were on the scene nine minutes later, which is a very fast response time.
"They did everything they could have done under the circumstances, because the house was well ablaze when they arrived," he said.
"We have had reports that the house had a smoke alarm in it but it is not clear if the alarm was working."
Post-mortem examinations will be held in Palmerston North today.
"Those examinations will determine the cause of death for both victims," says Detective Nick Wilkie.
"At this stage there are no suspicious circumstances and the matter will now be handed over to the coroner.
"Police and the fire service would like to extend condolences to the couple's family at this very trying time for them."
The family gathered in Tolaga Bay at the weekend.
- Gisborne Herald
