A crime-fighting charity has helped towards an increased £20,000 reward to solve the mystery of who brutally bludgeoned a house-sitter to death with a claw hammer.

Sussex Crimestoppers and Sussex Police have each contributed to half the reward for information leading to the arrest of the killer of Valerie Graves on the nine-month anniversary of her violent death.

The 55-year-old was found dead on December 30 while house-sitting at a friend’s house in Bosham.

Detectives believe she was attacked in her bed during the night by an intruder and hit multiple times in the head.

The grandmother had only recently moved back to Sussex from Scotland to help care for her elderly mother in Bracklesham Bay at the time of her murder.

A Crimewatch TV appeal in April led to some new leads for police but her killer still remains at large.

Angela Hollinshead, Crimestoppers’ area manager for Sussex, said: “Valerie’s murder was extremely brutal and her family has been devastated by her death.

“It is hoped that, by increasing the reward, this may assist in convincing someone to come forward and provide us with the critical information that may solve this crime.”

Detective Superintendent Nick May from the Surrey and Sussex Major Crime Team, said: "We are appealing to anyone who has any information or knows the person who has done this.

“You may have your own concerns or suspicions about this person already but for your own reasons have not yet come forward.

“Let me reassure you that we can support you whatever your concerns but this person must be caught."

Anyone with information on Valerie’s murder should contact Crimestoppers anonymously on 0800 555 111 or through an anonymous online form at www.crimestoppers-uk.org.