More than 100 police officers and staff are now involved in trying to track down the killer who brutally stabbed Peter Wrighton in Norfolk woodland.
The 83-year-old was found dead some six miles from his home village of Banham between Attleborough and Thetford.
Out walking his two dogs, Mr Wrighton was stabbed in the head and neck.
More than two hundred people have already come forward to help in the police inquiry but officers are still trying to trace key witnesses.
- Click to watch a report by ITV News Anglia's Malcolm Robertson
A community shaken after an elderly man was knifed to death is launching a dog walking buddy scheme to enable people to feel safe again.
The family of an elderly dog walker who was stabbed to death in Norfolk woodland have described him as ‘mild-mannered and gentle’.
Police have more time to question a man over the brutal stabbing of a pensioner - having spoken to more than 700 people at the scene.