Police in the UK investigating the unsolved murder of a grandmother as she house-sat for friends are set to start voluntary DNA screening.

Men who live, work or visit the Bosham area of West Sussex are being urged to eliminate themselves from suspicion following the killing of Valerie Graves (55).

The DNA screening will take place at the Millstream Hotel in the village from Wednesday.

It is the latest move by detectives who have launched a large-scale manhunt for the killer of grandmother and mother of two Ms Graves.

She is believed to have been killed with a claw hammer in a ground floor bedroom in Smugglers Lane, Bosham, on December 30th in 2013.

She was bludgeoned as she house-sat with her sister Jan, mother Eileen and her sister's partner, Nigel Acres, while the property's owners went abroad for Christmas.

Detectives released this photos of a hammer which they believe was the weapon used to kill her | Image: Sussex Police

More than 9,500 people have been interviewed by police, a stg£20,000 (€26,213) reward has been offered, a BBC Crimewatch appeal has been made and a limited DNA match of a suspect has been yielded.

But despite an exhaustive inquiry, no one has been charged.

The death of Ms Graves shocked the small community of Bosham, which featured in an episode of the ITV crime drama Midsomer Murders.

Last month, Ms Graves's two children Tim Wood (32) and Jemima Harrison (3), spoke - along with Mr Acres - ahead of the first anniversary of her murder.

The family said Christmas was put "on hold" as they faced their first festive season without her and as her murderer still remains at large.