messaging apps to set up private group chats and round up thieves at one time. bay area nordstrom, louis vuitton stores were organized on snapchat, where messages are capable of disappearing. what's's app, telegram and signal provide encrypted messages and tmblr has messages just for shoplifterss. >> they tell people where cameras are at the stores and teach them how to do it. somebody will post, i'm a newby, how do i do that? this is what you need to do. reaching out to a large group of people, we want to hit this particular center, let's go. >> investigators say suspects often don't know who else is