Psycho at the grocery store

Two weeks ago I went grocery shopping during the middle of the day.  I was going around, slowly checking things off my list up and down the isles.  As I was going around I noticed a guy in a black leather coat standing by the milk.  When I came back around to that side of the store again he was still there.  I had the thought "that's weird that he can't decide on what kind of milk to buy." But, I kept going about my business.
More isles and 7-8 minutes later it was finally time for me to head to the milk fridges.  I emerge from my last isle and the indecisive guy (with a mustache) is still there.  The mustache really should have tipped me off that this guy was worthy of a Criminal Minds/SVU episode about him.  (Kidding! Kidding! Mustaches are not always creepy. ;) Ha!)
So, I'm rolling up to the milk and this guy with a single item in his cart is staring me down.  As I approach he cracks a smile.  Side note- Since I worked in a dental office for a while I can't help but notice a bad implant on tooth #9. It's either that, or he has some serious perio issues because right above his tooth is a big black/gray spot  in his gums that I can't help but stare at as well.  By this point I'm smiling politely back at the man and he starts to talk to me.  That was weird in and of itself.  You don't chat it up with strangers in the grocery store... this isn't utah county, it's Boston!
He says to me, "I seen you over there and I just had to see what you were like......" -pause- -pause- (I'm shocked at this point, and not sure if I should say thank you or go call the cops.) He continues, "Oh, I'm Steve" and he extends his hand for a hand shake.  I'm floored by this point and I can almost see this exact moment at the beginning of one of those crime shows.  I was thrown off a little by his over-anxious smile and eagerness to speak with me.  So, following my gut - I didn't shake the man's hand.  I said, "It's nice to meet you Steve.  Have a nice day." -with a tone that let him know this was the end of the conversation.  I turned, grabbed my milk, and headed for the door.
When I was checking out I noticed Steve at the front of the store looking down an isle.  By this point I was praying that I could get out of there with out any further interactions with Steve.  I finally get all squared away and head out to my car.  I put all my stuff in the car and as I'm putting my cart away I notice Steve two cars away from me, putting two items in the back of his black sedan. Neither one of which was milk....