Police have released a CCTV image in relation to a sexual offence investigation.
The victim, a girl, was walking her dog in fields that back onto Frosts Garden Centre between Woburn Sands and Old Farm Park, north of the railway track, between 3pm and 4pm on Friday 14 April.
An offender approached the girl, made a sexual demand towards her and threatened her with a knife.
The victim reached for her phone to call for help and the offender ran off through the fields in the general direction of Old Farm Park.
"We appreciate the CCTV is not great quality, but we hope anyone who knows the man will recognise him or his clothing," police say.
"If you are the man in the CCTV or you know who he is, please call us on 101, quoting reference 43230162576."
