Detectives investigating a house fire which killed six members of a former Hampshire family are treating the deaths as murder, police said tonight.

Dr Abdul Shakoor, who worked Winchester's Royal Hampshire County Hospital until last year, lost his wife and five children in the blaze at their family home in Essex.

Sabah Usmani, 44, sons Muneeb, nine, and Rayyan, six, and daughter Hira, 12, died in the fire in the early hours of October 15 at the house in Barn Mead, Harlow.

A third son, Sohaib, 11, and daughter Maheen, three, died later in hospital. Dr Shakoor, who tried to rescue his family, was the only survivor.

Essex Police said tonight that evidence from fire scientists indicated the likely cause of the fire was “malicious ignition”.

Detectives from the Kent and Essex Serious Crime Directorate had initially treated the incident as a suspicious fire.

Senior investigating officer Detective Superintendent Rob Vinson said: ''This is now a murder investigation. We believe that someone burgled the house and then caused a fire that took the lives of six innocent people.

''Someone knows something about this incident and for whatever reason has not come forward to tell police what they saw or know.”

Appealing for information Mr Vinson said: ''Dr Shakoor has had to find the strength to cope with this terrible tragedy. No one can imagine the pain of losing your whole family in such a horrible way. I need to find answers. I need the public to tell me what happened on that night.''

Dr Shakoor discovered the fire at his home and battled hard to save his family, suffering the effects of the dense smoke and also minor burns as he tried to get them out.

Speaking publically for the first time at the funeral of his wife and children last month, which was attended by four hundred mourners, Dr Shakoor broke down in tears and told how he had suffered an “irreparable loss.”

He told the Harlow Islamic Centre: “It is a shocking and heartbreaking tragedy to myself, immediate family members and close friends that within such a short period of time I lost everything in my life.”

Tributes were paid by friends and former schoolteachers in Winchester, where the family lived until a year ago.

Hira, Sohaib and Muneeb all attended Stanmore Primary School while the family were living in Winchester.

Julie Reed, who taught Muneeb at Stanmore, said: “My reaction to the news was disbelief. I thought 'How could that have happened to such a loving family; such a wonderful family; such a special little boy?'”.

Former Stanmore head teacher Amanda Jones, added: “They were just a lovely family and very supportive of the school so it is a huge loss.”

The Princess Alexandra Hospital NHS Trust in Essex, where Dr Shakoor currently works, launched a fund to help him through the tragedy.