If there is economic prosperity then there is bound to be some crime that follows suit, there is always someone looking to make a quick buck.. Unfortunetly there are some who do not wish to make an honest quick buck :(

An alternative reason why there may be crime in Qatar would be out of necessity, there are alot of workers who are abandoned by corrupt companies and are left to fend for themselves, at this time Qatar does not have an easy means of getting help if your in that situation and when it comes down to surviving then people will not hesitate to steal or commit a crime just to make ends meet.

Thats my .02 cents