Stalk the guy who traded with u until he is in a dark secluded area. Once the coast is clear sneak up behind him and chloroform his ass. Then put him in the trunk and bring him to an abandoned warehouse. Tie him up and once he wakes up u do whatever it takes to make him talk. If he refuses to talk just put some supertweeters right next to his ears and crank them up, that should do the trick. Once he provides the whereabouts of the missing screws u chloroform him again and dump him in a bad neighborhood late at night then go get your screws. Problem solved...