In the evening of very first day I got hit by a surprise, An Arab local who seems drunk came in, found me sitting in the corner smiling at everyone. He came right to me and asked for my visa and Emirates ID Card. I told him that I have arrived only a day before and showed him my tourist visa copy. He said he is from CID and can arrest anyone at will. I was amazed and a bit scared too. Luckily the hotel senior waiter came in and told him in Arabic that I am a guest of the owner and he is calling the owner as my friend was not around at the moment. The Arab guy told him not to call and he was just on routine inspection and left without saying anything.
The waiter then told me not to worry, and he know these guys and they are not Emirates local but Arabs from neighbor countries and what they do is that they catch foreigners or new comers, tell them that they are from CID and they have suspicious news about you which they want to investigate and then take Emirates ID Card or passport and then ask you for money like 300 AED to 500 AED to give you the documents back. But this event scared me a lot from the name CID till I had a real encounter with CID guys and I experienced that they are the most decent and civilized from all other security agencies.