Philadelphia Police say the number of car thefts in the city is rising.
Authorities say there have been more than 4,500 reported car thefts year-to-date, which is up six percent from one year ago.
They said that 25 percent of those thefts are because someone’s keys have been lost, stolen, or left inside their car.
Officials think it's going to get worse because the weather is getting colder outside and many people want to leave the heat running in their cars.
Police say that thieves like to watch and wait and it only takes them seconds to jump in your car and drive away.
Police say that you should know where your keys are at all times, do not leave your keys in your car while parked outside your home or a store, and do not leave your car running unattended.