A man threatened staff at the Express Hair Salon in St Peter’s Walk, Northampton, on Saturday.
The incident happened between 4.20pm and 4.40pm, when a man went into the salon and threatened a member of staff.
The man was removed from the salon by an off-duty police officer, who was then helped by a second off-duty officer.
There were a lot of people in the area at the time and police would like to talk to anyone who may have witnessed the incident.
A 25-year-old man from Northampton was arrested in connection with public order offences and has been released on police bail.
Anyone with any information should call Northamptonshire Police on 101. Alternatively, information can be given anonymously to Crimestoppers on 0800 555 111.