Wiltshire Police have issued an urgent appeal for information about the man in this CCTV image.
He is described as a white male, about 6ft tall with a slim build and short slicked back black hair.
He is thought to be wearing blue jeans, and carrying a rucksack.
If you see him, do not approach him.
Call police on 999 immediately quoting log 153 of today, giving as much detail as you can about his location and direction of travel.
