A detective has promised never to give up his hunt to find the killer of grandmother Lea Florentina Brooke.
On Monday, it will have been six years since she was murdered in her Sandal Grange home by arsonists.
Mrs Brooke, 81, was asleep during the early hours of November 10, 2008, when white spirit was poured through her letter box and set alight.
Detectives were convinced that the grandmother, who never got to meet her first great-grandchild, was the victim of mistaken identity.
Her killer has never been brought to justice.
Det Sup David Pervin said: “Lea’s death was a tragedy for her family and for everyone that knew her.
“She was very active, well known and respected in her community and there is absolutely no reason to suggest why she would have been targeted.
“The person responsible should know that both myself and fellow officers will never give up the hunt to find them and to bring them to justice.”
Mrs Brooke was an active member of the community and regularly attended Wakefield Golf Club in Sandal.
She devoted her time to helping others through the Inner Wheel Club of Wakefield, which she had been a member of for more than 50 years.
In the hunt for Mrs Brooke’s killer, a reconstruction was broadcast on BBC’s Crimewatch in 2011 but no new witnesses came forward.
One theory is that the arsonist was targeting Mrs Brooke’s son, Howard Brooke, who ran a construction business and often stayed at his mother’s home.
Det Sup Pervin said: “I personally cannot understand how someone could live with the guilt and obvious torment of committing an act such as murdering a defenceless grandmother in their own home, or knowing and shielding the killer. “You can only assume that such knowledge must, over time, eat away at the person responsible.
“Lea’s family have lived for six years now without answers but with the knowledge that her killer is still out there.”
Anyone with information should call Det Sup Pervin on 101 or call Crimestoppers anonymously on 0800 555111.