San Diego police believe they have cracked a brazen burglary ring that stole items from up to 200 houses in La Jolla, often while residents were home. The burglars often simply slashed a window screen, reached in and grabbed a purse, kitchen appliance or whatever was handy, police said. "Some people woke up in the morning, came downstairs and found that what they had left on the kitchen table last night was gone," Sgt. Robert Peterson said. Police said the ring, concentrated in upscale La Jolla, has operated for six months. Police stumbled onto the case two weeks ago when they arrested a car prowler. During questioning, the man told detectives about other car prowls and residential burglaries in La Jolla.