Need some good advice?

hey i got this friend who came over yesterday and when he was over he asked if he could have one of my games and i said no so today i was going to play the game abd i couldnot find it where i had left it so im thinking that he stole it so i looked around for it and i cant find it so i called him and asked him if took and he said no but i just cant stop thinking that he stole it because it kind of has to be more than coincidence that the first day he ask if he could have the game and me saying no and then the game going missing and i did leave the room a little bit so he could of stolen it then so do you think i should go over to his house and wait until he leaves the room and look and see if he has it and if he does steel it back