Auto thieves have been busier than usual in Montgomery County in recent months using advanced technology to steal property and cars. Montgomery County police said thieves are targeting Kias, Hyundais, Infinitis and Hondas using expensive devices that can duplicate the signal from a vehicle's key fob. Montgomery County police call the devices “replicators.” Fields said the thieves use the device to find signals coming from key fobs that will unlock car doors. In Montgomery County, police said since the first of the year, officers have arrested more than 90 juveniles for stealing cars and more than 40 adults.