Officers investigating the attempted robbery at a bookmakers in Houghton Regis have released CCTV stills of three men they need to trace in connection with the incident.
The incident happened on June 19 at approximately 8.55pm when the three men entered Ladbrokes on Hillborough Crescent.
The men ran towards a member of staff who managed to lock herself in to a secure room. The men then left the scene empty handed.
Detective Constable Matthew Shepherd, investigating, has released these pictures in a hope that someone can help identify those involved.
Anyone with information about this crime can contact DC Shepherd, in confidence, at Luton Police Station, on 01582 394448, or Bedfordshire Police on 101, or text information to 07786 200011.
Alternatively you can contact the independent crime fighting charity Crimestoppers, anonymously, on 0800 555 111.