During the past three weeks, police have received reports of seven similar incidents across the city.
The carparks targeted include the Range on Water lane, Southernhay east, Waitrose and Sainsburys on Alphington Road.
A smartly dressed man is targeting lone older women and men, pretending he needs change for the ticket machine.
So far, around one-thousand pounds has been stolen.
Teenager jailed for train station rape
He also sexually assaulted a girl on a train
Anger over planned Plymouth road closure
Traffic would be diverted to congested Deep Lane Junction
Cyclist in serious condition following hit and run
Bovey Tracey road closed for several hours
Paignton shopping centre to become car park
'It has the potential for a catalytic regeneration development'
Devonport dockyard is out of 'special measures'
Safety improves after 12 years of 'enhanced attention'
Duke of Cornwall visits Cornwall
VIDEO Prince William makes pasties
