Hundreds of men have provided DNA samples to police who are carrying out voluntary screening in an attempt to find a grandmother's killer.

Police said 725 men have attended the Millstream Hotel in Bosham, West Sussex, since screening began last week as detectives work to solve the murder of artist Valerie Graves.

The 55-year-old, who had only just moved to the south coast after living in Scotland for many years, is believed to have been bludgeoned to death with a claw hammer in a ground floor bedroom as she house-sat for friends in Smugglers Lane, Bosham, on December 30 2013.

She was staying in the house with her sister Jan, mother Eileen and her sister's partner, Nigel Acres, while the property's owners holidayed abroad over the Christmas period, Sussex Police said.

The mother-of-two's killer still remains at large despite a £20,000 reward being offered by police, a Crimewatch appeal being made and 9,500 people being interviewed in relation to the investigation.

Detective Superintendent Nick May, from the Surrey and Sussex Major Crime Team, said men aged 17 and over have been asked to give a voluntary sample which will be compared to the limited DNA profile they have of Ms Graves' killer, in order for them to eliminate a large group of people from the investigation.

The process, which is painless and takes no longer than 10 minutes, requires men to provide a thumbprint and to have a swab taken from the inside of their mouth, police said.

The samples will only be used to check against this particular crime and their DNA profile will not appear on any database.

Legal safeguards are in place to ensure they are not used for any other purpose, the spokeswoman said.

She added: "We are very pleased with the response so far to our appeal for all men aged over 17 who live or work in Bosham, or who visit the area, to volunteer their DNA and provide a thumbprint, and we hope many more will come in for just a few minutes to help us in what is the biggest voluntary mass DNA screening in our history."

The DNA screening sessions will run until Thursday and again from February 2 to 7, and February 10 to 15.

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' two children Tim Wood, 32, and Jemima Harrison, 35, spoke - 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.

Anyone with information about the murder should call 101, quoting Operation Ensign, or call Crimestoppers on 0800 555111.

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