The body of Peter Wrighton was found in heathland near East Harling, in Norfolk, on 5 August.
Detectives said they have now taken more than 170 calls since Wednesday and had received more dash-cam footage, while house-to-house inquiries were also being carried out.
Det Supt Andy Smith, who is overseeing the investigation, said: “We are extremely pleased and grateful for the response from the public yesterday at the scene, which has helped us to identify further witnesses.
“We are still keen to hear from any members of the public who were in this area on the relevant day and who have yet to speak to us.”
Mr Wrighton, from Banham, had been stabbed in his neck and head – with his body found near the Fiverways Junction, three miles south of East Harling.
Earlier, a minute’s silence was held in his memory at an annual show for the Thetford and District Canine Society, where the grandfather and his wife of 59 years once served on the committee.
The retired BT engineer had been walking his dogs Gemma and Dylan when he was attacked.