A £10,000 reward is being offered to help catch those responsible for the death of an 87-year-old man following a robbery at his home.
Arthur 'Bob' Gumbley, was attacked at his home in Endwood Drive in Sutton Coldfield, on the evening of 21 November.
Despite being in good health before the attack, his condition deteriorated in hospital and he passed away in the early hours of Tuesday 12 December.
Four people - two men and two women - all from Birmingham, remain in custody after being detained in connection with the fatal assault.
Crimestoppers is now offering cash for information leading to the arrest and conviction of those responsible.
Mr Gumbley's family said: "The true impact of this has not hit us yet.
"Our dad was always a very important person in our lives and was loved very much by us all.
"He truly was a person that, not only us as a family, but the people that knew him, looked up to and respected.
"Words can't express the extent of our loss."