Montgomery County police are urging Bethesda and Chevy Chase residents to keep their car doors locked. Police are investigating forty-five thefts from vehicles since June 1st. Captain Paul Starks says the victims left the thieves easy entry by leaving their doors unlocked. Starks says in two cases there were spare keys left inside the vehicles. Those cars were stolen. He says many of the thefts have occurred in an area south of Goldsboro Road and along River Road and Massachusetts Avenue.