In a new wave of crime that occurs in an instant, thieves are cagily sliding into victim's cars and snatching valuables from open windows, in what police are calling "sliding."From Corbin, Ky., to Tampa, slippery sliders are being caught on camera all across the country. Sometimes the perpetrator is caught red-handed, but most of the time the victim has no idea until it's too late.Often operating at gas stations while customers are casually pumping fuel, thieves lying in wait pounce, snatching purses and other valuables, then running off."They're not looking for a confrontation," Houston police officer Jim Woods told ABC News. "They just want the property, because they know it's being left abandoned and you're not paying enough attention."And police say these types of crimes are on the rise.In an incident caught on tape at a Houston gas station, a woman pulled up and walked into the station as a man in a neighboring vehicle cased the inside of her car. Once she returned to the pump, the slider struck."It's very scary that someone could just surprise you and just steal all of your belongings," the victim said.Authorities say the best thing the public can do is lock car doors every time the vehicle is exited."It's yours, protect it," Woods said. "And the easiest way to protect it is keep it locked up, keep it with you, and don't leave it in the vehicle unoccupied."