A man wearing a motorbike helmet held up a Ladbrokes in Cambourne with a handgun
Police want to know if anyone recognises the robber's clothes.
Police have released CCTV of the moment an armed man carried out a robbery at a bookmakers in Cambourne.
They are appealing for information to help identify the robber.
A man wearing a motorcycle helmet went into Ladbrokes, in Broad Street, Cambourne, at about 7.20pm on February 17 and pointed what was believed to be a handgun at the cashier.
He demanded access to the safe but the member of staff locked himself in the back office and raised the alarm.
The robber stole cash from the till and made off.
DC Martyn Willis said: “I am appealing for witnesses who might have seen anything suspicious at that time or anyone who might recognise the clothing worn by the suspect.”