TV filmmakers have called in the Gazette and Herald to help solve a horrific murder mystery from more than 140 years ago.

The murder of four-year-old Francis Saville Kent shocked the country when the little boy's body was found in an outside privy at his home, Road Hill House, near Frome, on June 30 1860.

He had suffered the most appalling injuries. His head was almost severed and he had been stabbed in the chest. The murder received much publicity at the time.

Police were stumped by the crime and no one was arrested for it until five years later, when the boy's step-sister, Constance Emilie Kent, confessed to the murder.

But forensics expert Professor David Wilson is not convinced that Miss Kent was, in fact, the murderer. In a new series for HTV, Grave Detectives, he and presenter Chris Serle follow the trail of evidence.

Their investigations led them to the offices of the Wiltshire Gazette and Herald on Tuesday where there are bound copies of the Devizes and Wiltshire Gazette going back to the date of the murder.

Mr Wilson, who writes for The Guardian and The Independent and was once described by the Daily Mail as the thinking woman's Alan Titchmarsh, said: "This is a fascinating case and one that should make a great programme. We have featured a lot of cases from the Bristol area so it is really good to come to somewhere beautiful like Devizes to film.

"It is wonderful that the Gazette has this archive of old editions for us to use.''

The edition of July 5 1860 reported: "The usually tranquil neighbourhood of Road has just been fearfully agitated by the discovery of an appalling murder on the body of an interesting boy four years of age, named Francis Saville Kent, youngest son of Mr Kent, Sub-Inspector of Factories, residing at Road (Rode), just on the borders of Somerset, and a few years ago the occupier of Baynton House, near Erlestoke. It appears that Mr Kent has twice been married, and that his family consisted of five children, two of whom were the offspring of his second marriage. The deceased child was the second of these."

The reporter, recalled how foxed the police were by the facts of the case.

He wrote: "How an individual could have taken the child from his cot, placed the bed clothes tidily, carried him through the drawing room (which is on the ground floor), across the lawn, through a shrubbery, and stable yard, where a watch dog was loose roaming about, thence into the water closet, deprive the child of life, and decamp, without leaving behind the smallest clue to his guilt, or disturbing the inmates, or awakening the child, or coming into collision with the dog is a mystery indeed!"

It remained a mystery until 1865 when the boy's sister, Constance Kent, was brought to justice.

The Gazette notes in the edition of April 27 1865: "It is hardly a secret that nearly a year after (the murder), in consequence of an alleged confession of the crime by Miss Kent to one of her relatives, another attempt to investigate the matter was made by the detective officers, who had incurred the censure of a large proportion of the press and the public for their proceedings in the case.

"They found it unadvisable, however, to act upon the fresh information which had reached them, and it subsequently transpired that Miss Kent had been sent to a convent in France.

'Nothing more of a reliable character was heard of the case until Tuesday, when the startling intimation was conveyed to the chief magistrate that Miss Kent was in custody upon her own confession upon the terrible charge."

That confession was enough to convict Miss Kent and she was later hanged, but Prof Wilson is not convinced that the conviction is safe.

The TV team also visited the grave of young Francis in the churchyard at Coulston, near Erlestoke, not far from his father's first home of Baynton House. They spoke to vicar, the Rev Jean Hall, and church caretaker, Edith Earley.

Mrs Earley told the Gazette: "The boy was buried at Coulston because there was too much public interest in the house at Rode.

"It is a story that children in this area are taught and they take great interest in it because it is part of their heritage."

The programme is due to be broadcast in October.