The identities remained a mystery to police as they finalised autopsies and awaited the results of toxicology tests, while next of kin continued to go uninformed of the deaths.

Flowers and soft toys were left near the Peter Coppin Street house in tribute as Canberra police remained on the scene of what they believe was a deliberately lit fire.

ACT Policing said its investigations continued and that detectives were taking a "large number" of avenues to discover how the people died and were burnt in a fire that tore through the community housing property just after 9am on Monday.

"To this end, investigators are working as quickly and methodically as possible," police said in a statement.

Media reports on Wednesday said that ACT Policing was pursuing a murder investigation into the deaths and that it would review video footage taken by a witness of the fire for any sign of a getaway car for the suspected murderer.

Police would not confirm the reports, nor whether they had any suspects.

ACT Policing on Tuesday said they released a man after questioning on Monday, but no charges had been laid.

The fire that gutted the house and led to the grim discovery of the bodies in Canberra's north was deliberately lit, police said.

Neighbours said a mother and two children lived at the house, and Detective Superintendent Scott Moller said fire accelerants were likely used and that there were multiple "seats of fire" in the house.

Firefighters discovered the bodies inside the house while battling the blaze on Monday.

Police on Wednesday said it recognised the interest in the matter and noted "speculation on the circumstances".

"We thank the community for its information and support to date regarding this incident."

Police urge anyone who may have any information that could assist police to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website.