A 19 year man from Harlow was arrested on Tuesday on suspicion of murder, attempted murder, arson and burglary by Essex Police investigating the fatal fire in Harlow last October that took the lives of six members of the Shakoor family.
He has been questioned about his involvement in the burglary and fatal fire at Barn Mead, Harlow on October 15, 2012 and has been bailed until June 27, while further enquiries are undertaken.
Police investigating a house fire in Harlow which killed six members of the same family have made a fresh appeal on the BBC's Crimewatch programme. It featured an interview with Dr Abdul Shakoor, who lost his wife and five children in the blaze last year.
The appeal also featured previously unseen footage from the night of the fire, which was recorded by the emergency services.
Detectives investigating the house fire in Harlow that killed a woman and all five of her children, are now treating the deaths as murder.
The blaze was started by burglars in the lounge, and the flames then spread throughout the house.
There is a £10,000 reward to help catch the killers.
Lauren Hall reports.
Essex police say they've received a number of calls after a TV appeal over the house fire that killed a family of six in Harlow.
Dr Sabah Usmani and her five children died after the blaze last month. It's now being treated as murder.
In a fresh appeal on the BBC's crimewatch programme last night, police asked for information about a laptop stolen from the house on the night of the fire. Detectives described the case as tragic and unprecedented for the force.
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A spokesman for Essex Police said:
A house fire that killed a mother and her five children in Harlow, Essex, last month is now being treated as a murder investigation, Essex Police said tonight.
Crimestoppers have said it would pay the reward for information leading to the arrest and conviction of those responsible.
Ann Scott added that people had "nothing to fear" by contacting Crimestoppers as all witnesses could remain anonymous.
A £10,000 reward is being offered for information on an Essex house fire that killed a mother and her five children.
The blaze killed Sabah Usmani, her daughters Hira and Maheen and her sons Sohaib, Muneeb and Rayyan in Harlow last month.
Police are keen for information on a group of young men seen outside the house on the night of the fire.
Police in Essex are speaking to two young people, seen throwing away a laptop bag on the night of a fatal fire.
It's been revealed the house in Harlow - where Sabah Usmani and her five children died - was burgled on the night of the blaze.
Officers think several items, including a laptop, were taken after the family had gone to bed but before the fire was discovered.
Police reveal the home, where a mother and her five children were killed in a fire, was burgled on the night they died.
Sabah Usmani and her children were all killed after flames swept through their home in Harlow in Essex last month.
The children's father survived.
Police have said his laptop bag was discovered abandoned, two weeks after the fire.
Ria Chatterjee reports on the latest developments in the investigation.