her last sighting was about 7:30 tonight south of ocean city maryland. but well off the coast. we don know where she will turn up next. but we do know that twitter is certainly watching. the fake sitter twitter handle at mary lee shark has drawn more 50,000 followers. that handle by the way is not affiliated with o search the company tracking her every move. >>> it's almost the end of an era. david letterman will host his final late show from the ed sullivan theater on wednesday. but before he does, we're continuing to take look back on on late night tv. cbs news correspondent susan marques has more. >> oh, kitty. moew. >> reporter: dave's humor has always been a little off beat. a little absurd. >> what do you have there? >> pizza. >> can you take the pepperoni off the pizza and leave it on the sidewalk? >> there they go. >> and destructive. dave stuck with a particular kind of comedy. >> there was a sense of irrelevant river answer and sort of anything can happen.