a slough of smash-and-grab burglaries at high-end retailers across the country has authorities on alert. flash mobs carrying out the robberies are causing concern right now. cnn's brian todd has more. >> reporter: on the left thieves violently hack away at a jewelry glass case near san francisco. on the right a louis vuitton store is ransacked outside chicago. authorities say they made away with more than $100,000 of handbags and other merchandise. at this in order stram near l.a. on wednesday, at least five people went in and did more than steal valuable merchandise. >> a number of suspects entered the door here behind me and took several high-end purses. unfortunately, we do have a security guard here that was