This is probabally a long shot, seeing as its quite an old game now, and if I recall correctly it wasnt particularily mainstream either. However considering the nature of this site, I figure there might be someone here who has a idea about what I'm talking about. I've tried to provide as many details as I can remember.
It was kind of a strategy adventure game, and was all very indepth and complex, you had to scout out possible targets, observe the area for several weeks taking note of everything from the staffs working hours, security patrol routes, cameras and alarms, whilst planning your heist right down to the smallest detail.
You could even hire accomplices each with there own specializations and personalities, from professional cat burglars, electricians, to under paid security guards. Inexperienced accomplices might trip off an alarm, leave behind finger prints, whilst untrustworthy ones might evenbottle it and rat you out to the police during the post burglary police investigations.
You started off knocking off small buildings such as shops and post offices, working up to auctioneers and banks, and eventually really big jobs like stealing the Crown Jewels from the Tower of London.
The whole game was very detailed, and highly polished, with great graphics for the time.