Police are warning cash machine users to be extremely cautious of skimming devices after five were found.
Police in West Sussex have received numerous reports of devices being used on cash machines.
They consist of a strip fitted above the keypad with a pin-hole camera and a reader fitted to the card slot.
They are made in the same colour as the ATMs and at a casual glance are virtually impossible to spot.
When a customer uses the machine, the cash transaction takes place as normal and is unlikely to arouse suspicion, but the fraudulent card reader has recorded their card's details and the camera has filmed them entering their PIN on the keypad.
PC Philip Dodd, who has been investigating the reports, said: 'A distinctive black adhesive is used to affix the devices and when looking at other ATMs, we have discovered the residue of this adhesive on a number of them.
'It is reasonable to assume that these machines have been targeted in the past, but we are unable to establish when. Look closely at cash machines and if you have any doubts, don't use them or make sure that you cover your keying hand with your other hand when you put in your PIN.
'Report your suspicions to the bank if it is open or to the police.'
Anyone affected should call Sussex Police on 0845 60 70 999 or Hampshire Police on 0845 045 45 45 or Crimestoppers on 0800 555 111.