The suspected murder of a mother and her five children in a house fire is now being treated as a cold case, the BBC has learned.

Dr Sabah Usmani and her five children – Hira, 12, Sohaib, 11, Muneeb, nine, Rayyan, six, and Maheen, three – were killed by the blaze at their home in Harlow in October 2012.

Detectives say there are no longer any viable lines to investigate but will "continue to assess any new information".

The children's father Dr Abdul Shakoor, 59, who was the only survivor that night, says he fears he will die before the case is solved.

Inquiries become cold cases when police believe a homicide has been fully investigated but remains unsolved.

It does not mean the case is closed but detectives will not actively pursue it day-to-day.

Shakoor has been told that unless new information surfaces, Essex Police will review the case in a decade's time.

"Who knows in 10 years whether I will be here," he told the BBC. "I don't know whether I'll be alive at that time."

He said the development from police was "very disappointing" news.

"I know that Essex Police have done a really great job and I still feel that they would like to resolve this case as a top priority. It is the matter of the six lives lost, all innocent. In one night, everything was taken away from me."