Police are appealing for information about two Audi cars seen in a Powys town during a late-night robbery at a building society.
Two men wearing reflective jackets attacked security staff who were delivering cash to the Nationwide, in Newtown, on Monday at about 2200 GMT.
Police said a white Audi A3 and grey Audi A4 were seen in the area and they believe the cars were involved.
Thieves escaped with a "large amount" of money.
They used sledge hammers to smash the front door and stole an undisclosed amount of money from a cash machine.
Officers said the raiders left the scene at speed, and the vehicles were also seen travelling along the A483 road.
People who saw the cars between 1830 and 2230 on Monday are asked to contact Dyfed-Powys Police on 101, or the independent charity Crimestoppers anonymously on 0800 555111.