You know that many laptops have tracking software installed so that they can be traced when stolen, don't you? That's caught out a few thieves. Obviously if you try to access a computer that you have "found" you will be breaking misuse of computers laws. But I guess you know that.
This would appear to be your first post, so how can anyone have told you that your computer is stolen? I think you have bigger problems than being locked out of your computer. I can't help with those, but the computer problem is easy - take it to your nearest Apple Store and they will sort it out for you.
Try to be more polite with them than your sole post on this site has been.