Ford owners in Penarth, south Wales, are being urged to remain extra vigilant following a spate of thefts targeting car stereos.
Police believe the overnight crime spree in which 10 Ford Focus cars were broken into, and a series of thefts prior to that, were sparked by an "urban myth".
Criminals believe a microchip in the radio can decode satellite television receivers, although there is no evidence it does so, officers said.
The latest incidents happened in the Cogan area of the town and thieves made away with several CD radios after smashing the front windows of the Ford vehicles and leaving their owners with potential car insurance claims.
Three suspects - two wearing black jackets and one in a grey hooded top - were disturbed at around 12.20am on Monday in Harriet Street, Cogan, police said as they appealed for help to catch the thieves.
Penarth Neighbourhood Inspector Chris Owen said: "We have seen similar spates previously, which are linked to an urban myth about the radios containing a special microchip. Experts have concluded the microchip cannot be used in this way and the thieves are wasting their time.
"But we need information about who is responsible for stealing these radios and where they are selling them.
"They are probably offering these radios for sale cheaply and would ask anyone who is offered a cheap Ford radio to decline and call us immediately."
© Press Association 2011