DCI Karen Trego from the Force's major crime unit said: "We are pleased with the response from the public following Monday's press conference. However, we now need to speak to anyone who saw Mr Charkaui on the day of the attack, as we are trying to piece together his last movements."

Mr Charkaui and his wife, Krystina Charkaui, were in their home at 52 Dunsham Lane, Aylesbury, when two men wearing balaclavas used a spade to smash the rear patio window to their house.

Mrs Charkaui ran upstairs to where her husband was, followed by one of the men, who then struck her across the face. Her husband was then struck over the back of the head and knocked unconscious.

The 57-year-old, an orderly at Stoke Mandeville Hospital, was admitted to the JR2 Hospital in Oxford, where he died as a result of head injuries at 6.10pm on Friday, March 23 without regaining consciousness. A post mortem on Sunday, March 25, confirmed he had a fractured skull and died as a result of a head injury.

More than twenty Thames Valley Police detectives, as well as forensic and search officers, are working on the murder case, but officers are still looking for the murder weapon. DCI Trego said: "We are almost certain we are looking for a spade and not a shovel and I am urging anyone in the vicinity to check their gardens for a spade that does not belong to them."

Five spades and shovels, which are currently undergoing forensic analysis, have so far been handed in at Aylesbury police station.

Although the attackers were wearing balaclavas, glimpses caught by the victim showed they were white or light-skinned.

Anyone who was in Dunsham Lane or Elmhurst Road between 9.30pm and 11pm on Monday, March 12, or who knows who may have committed the crime is asked to contact DCI Trego at Aylesbury Police Station on 0845 8 505 505 or, if you don't want to talk to police or give your name, call the Crimestoppers charity on 0800 555 111.