A teenager was approached by a man who made threats to hurt him.
The incident happened outside Greggs in Willow Place, Corby, between 3.15pm and 3.50pm on Friday, March 29.
The suspect is described as white, in his early 30s, about 6ft and stocky.
Witnesses to the incident, or anyone with information, should call Northamptonshire Police on 101.
Alternatively, they can call Crimestoppers anonymously on 0800 555111.