Police are warning Bicester householders to take extra care after a series of burglaries using cold calls to identify target homes.
Officers believe cold calls are being used to identify Asian families up to a month before break-ins, and are warning householders to take extra care.
Police are linking burglaries taking place in Bicester, Banbury, Oxford and Aylesbury since mid-July.
The break-ins are usually on Tuesdays, Thursdays and Saturdays between 12pm and 5pm.
The gang gains entry by smashing a window or using distraction techniques.
Burglars have been described as white men in their 20s and 30s.