The detective leading our investigation into the death of a mum and five children in Harlow is appealing directly to the writer of a letter who states they have key information on what caused the tragedy.

Dr Abdul Shakoor was the sole survivor of a fire which claimed the lives of his wife Dr Sabah Usmani and five children Hira, Maheen, Sohaib, Muneeb and Rayyan in Barn Mead in October 2012.

The family were asleep at their terraced home at 1.40am on 15 October 2012 when the fire took hold of the downstairs of the property. A silver Ford Focus was set alight at the same time in close proximity to the house fire.

The home was quickly engulfed by flames and smoke.

Despite Dr Shakoor’s desperate attempts to raise the alarm and save his family, the fire took hold and Dr Shakoor’s wife and children did not survive.

Our murder investigation, called Operation Shakespeare, has been running for almost 14 years.

To date, no one has been held to account, but our work has continued, with more than 70 police officers and staff focused on the incident and the circumstances around it, about 500 people coming forward to give witness statements and almost 2,000 items being examined.

Now, we’re asking for the author of a letter sent to us to come forward and speak to us directly.

The anonymous letter, sent directly to Essex Police, sets out a number of details which we are very keen to progress. But to do so, we need this person to come forward and speak to us directly.

Detective Chief Inspector Louise Metcalfe, who is leading Operation Shakespeare, said: “This letter is clearly written by someone who wants this investigation to progress just as much as we do. They clearly want to Dr Shakoor get justice for his family.

“The author references the ‘nightmare’ of having information but not feeling able to share it. To that person, I’m saying: ‘You can share what you know – you will be treated fairly. Your information could be what leads to a person or people being held accountable for tearing the Shakoor family apart’.”

DCI Metcalfe added: “The whole of this investigation team remains committed to securing answers for Dr Shakoor. He has lived for too long with questions over how he lost his family.

“I would urge anyone with any information on what happened in Barn Mead, Harlow, in October 2012 to please come forward.”