Samsung BlackJack II SGH-i617

I just found a sgh i617 lying on the ground. It has no sim card in it, but otherwise is in perfect condition. I have at&t service so I put my sim in the phone and it came on asking my pass code which I entered. It confirmed. Then it told me to type in password to unlockphone. I tried several and no luck. I'm sure whoever tossed the phone out the window of the car (I'm guessing from location) AFTER they removed the sim (dont understand that part, probably stolen) has that password. Is there any way around it?