WINONA, Minn. – A man walking his dog on the levee at the East End Marina came back to his car to find it stolen. He told police that foolishly he had left his keys in the ignition. Police said a couple bikes had been tossed in the grass next to where the car had been parked. There had been bikes stolen earlier in the day in the neighborhood, leading police to surmises that juveniles had dumped the bikes and driven off in the car. “Quite an upgrade,” one officer mused grimly. This was about 4 p.m. A couple hours later 16 blocks away, near the King Koin self-laundry at Center and Howard streets, a caller reported suspicious activity with seven or eight juveniles with hoodies up, some on bikes, congregating around a black car in an alley. Yes, the car stolen at the marina was black. When police turned into the alley, the kids scattered, some on bikes, some on foot. Police caught two of the juveniles, both from Winona, and turned them over to their parents. Charges are likely, police said.