Police now say the origin of the fire came from within the house.

The fibro home was destroyed in the blaze about 3am on Wednesday.

Mother Jackie Kovacs and six of her children made it out of the fire. Sadly, little Billy – who was trapped in the rear of the Housing Commission home – was not so lucky.

Firefighters pulled him out of a rear bedroom but he died in Bathurst Base Hospital from suspected smoke inhalation.

Detective Sergeant Joel Fawkner, who is leading Strike Force Goldstein in investigating the fatal blaze, yesterday said specialist investigators from the state crime homicide squad, property squad arson team, crime scene investigators from the forensic specialist group and members of the NSW fire investigation unit had spent the past 48 hours examining the site.

Sniffer dogs were also brought up from Sydney as part of the investigation.

Sgt Fawkner said the extensive forensic examination had ruled out the possibility of an object being thrown through the window into the house.

“The fire is believed to have originated inside the premises,” he said.

“That [Molotov cocktail] theory has been ruled out by the evidence.”

Sgt Fawkner added that police were still keen to speak to anyone who may have witnessed anything in relation to the fire.

“We have spoken to all the neighbours and Billy’s mum,” he said.

“We will do further interviews with the family next week.”

Sgt Fawkner said investigations into the fatal blaze would continue for some time. He urged anyone with information to contact Crime Stoppers on 1800 333 000 or Bathurst detectives.

Once the investigation is complete a report will be made to the coroner.

Details of Billy’s funeral have yet to be finalised.