Norfolk Police are carrying out searches close to the A11 in Thetford in the hunt for a missing man.
Tomasz Czech, 54, went missing from his home in Chester Way on Friday night. He left his home at around 6pm to take his dog for a walk and has not been seen since.
Mr Czech is described as approximately 5ft 8 in height and of average build. He was wearing a black jacket with green markings on it, blue jeans and black trainers when last seen.
He would normally walk his dog for in the wooded area and pathways next to the Little River Ouse towards Brandon.
The dog's collar was found at the side of the A11 near the Brandon Road roundabout. Police are now searching the nearby area for Tomasz and his dog.
Police want to hear from anyone who may have seen Tomasz or a loose brown boxer dog in the Thetford and Brandon areas.
Anyone with information concerning his whereabouts should contact Norfolk Police on 101.