Miniature Manipulator

Is there some secret "Rocket Science" kinda trick you need to use to get a little boy completely potty trained?  We will go along great for days and then.........well, you know.  For example, about 3 minutes ago my three year old struts through the living room NAKED!!!  "Baby, why are you naked?", I asked.  "I'm not naked", he said.  Now I have never claimed to be a genius of any kind or of any subject.  I am however fairly sure that I know naked when I see it.  The boy was naked.   My next question was if he had wet his pants.  He looked down at the floor and replied "no".  "Are your pant wet?".  To this he said yes.  I did the whole pep talk "You have to go pee pee in the potty, buddy" talk.  His reply to this was VERY intersting.  He claims that he did not wet his pants.......his Sissy did.  Really?  Hmmm.  Well, to begin with she isn't here.  Also the fact that there is no way she could wear his little Potty Scotty underwear needs to be considered.  I cannot recall the last time she wet her pants either.....I would guess it's been years.  I tried to explain to my little man that his "Sissy" could not have wet his pants.  He decided to change tactics.  His new claim?  "you did it Mommy".  WOW.  I had no Idea I had that kind of problem.  I better work on that!!!   I again tried telling him that Mommy did not wet his pants, he did.  He is still insisting that he did not wet his pants, someone else did.  I think I may be in big trouble.  He may go into politics.  My three year old has done something and is becoming a pro in misinformation and diversion.  I may need reinforcements by the time he starts Kindergarten.  Help me world!