Detectives investigating a murder have now set up a mobile DNA screening unit.

Last week a voluntary mass DNA screening session took place in Bosham at the Millstream Hotel, in the quest to find the killer of Valerie Graves.

On December 30, 2013, 55-year-old mother and grandmother Valerie Graves was found brutally murdered in her bedroom in Smugglers Lane, Bosham.

She had been staying at the property while the owners were away over the Christmas period.

Now police are also using a major incident vehicle which can be moved around the area for men aged over 17 who live, work or visit Bosham to visit and offer their DNA.

The vehicle will be outside the Co-op shop in Delling Lane, Bosham, tomorrow (January 28) from 10am to 2pm and outside the Tesco Extra store in Fishbourne from 3pm to 8pm.

Anyone who attends is asked to bring along photo identification, a passport or a photo driving licence.

An officer will fill out some details, check their identification and take a photo of them. Their thumbprint will be taken and a swab will be taken from inside their mouth.

The process is painless and should take no longer than 10 minutes. Police will only use the samples obtained 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 samples will be destroyed at the end of the investigation.

More than 800 men have already come forward since the screening sessions began last week.

The sessions take place at the Millstream Hotel in Bosham Lane, Bosham, until Thursday (January 29) and then from Monday, February 2, to Saturday, February 7, and again from Tuesday, February 10, to Sunday, February 15.

All sessions are from 10am to 8pm.

Just over a year on and Sussex Police says a significant investigation continues into the murder.

Anyone with information should call 101 and quote Operation Ensign or to call the independent charity Crimestoppers on 0800 555 111.