Conversation with a 6 yr. old

Me: Spence, I have a job for you. I need you to go do a load of laundry. Put just the whites into the washing machine, you don't have to do the soap today or start the water, I'll do that part. (normally he does everything, but he has a friend over this morning and I didn't want to be too mean by taking him away during play time, but he did need to do the job)
-Spencer went around the corner to the laundry room, I could hear him in there, I decided to go make sure he didn't put any bright red things in, because there were a few in the laundry room and because he was in a hurry to play, I thought he might just start throwing things in. I came around the corner and he wasn't in the laundry room, he was near the stairs/front door and looked shocked to see me.-
Me: Why didn't you put the clothes in the washing machine? You didn't even start yet...
Spencer: I, um... hummm. I see there is a screw sitting here on the stairs, I wonder who took it out. I should probably put it back so it doesn't get lost.
-He picked up a screw and a screwdriver from the stairs and walked over to the front door. He proceeded to put the screw back into the door knob. As a side note, I had just spent considerable time on the stairs with a child in time out and know for a fact that the screw and screwdriver were not there a minute ago. Also, if you see a screw on the stairs, do you immediately assume that it belongs to the front door? No, only the one that took the screw out, would know that. Hmm...-
Me: Spencer when you get done putting that back, come and put the clothes in. Why did you take the screw out of the door?
Spencer: What did you say?
Me: Why did you take the screw out?
Spencer: You think I did it?
Me: I know you did it.
Spencer: Oh, you saw me.
Me: No, Mommys just know when you do things...
Spencer: Oh, sorry, I'll put it back and not take it out again.
Me: Okay, then come and get the laundry started.
Spencer: Okay, I'm done, here's Daddy's screwdriver... don't tell him I used it!

He put the screw back tightly, he sorted the laundry and put the whites in, he then remembered he had a friend over and decided to join the playing already in progress in the other room. I didn't get angry, because of all the things he normally does, this wasn't that bad. He had gone into the laundry room, as instructed, but saw the screwdriver on the dryer. I don't know where he got the idea to remove the doorknob from the front door.