An author who questioned the guilt of the man jailed for killing TV presenter Jill Dando has written a book about notorious Essex murderer Jeremy Bamber.

Doubts raised in books by Scott Lomax about the case against Barry George were proved well-founded when the 48-year-old was cleared at a retrial, seven years after his conviction.

The crime writer has now turned his attention to investigating the case of Bamber, 47, who is in prison for life for shooting dead five members of his family at White House Farm in Tolleshunt D’Arcy back in 1985.

He interviewed Bamber in prison and has extensively questioned the man who was dubbed “callous,” “wicked” and “evil, almost beyond belief” by the judge at his trial.

At the trial of Bamber - who a judge ruled earlier this year should never be released - the jury was told the only other possible culprit for the killings was one of the five dead, Sheila Caffell, who might possibly have killed her adoptive parents and two sons before shooting herself.

Bamber has always maintained an unknown third party could also have been responsible, and claimed the jury should have been told of the theory.

• Jeremy Bamber: Evil, Almost Beyond Belief? is published in hardback by The History Press and is available priced £18.99 from bookshops and the website Amazon.