"Why would I need a stupid Charizard?" Because you steal Pokemon.
"I simply LOOOOOOOOVVVVEEEEE ground Pokemon, like Nidoqueen. Charizard is fire, one of the RIVAL TYPES to ground." Yes. Excatly why you'd want to steal one.
"I was helping Mrs. McMewtwo cross the street at the time." There is no Mrs McMewtwo. Liar.
"Then I was buying food for my ground Pokemon." Yea, and probably your new Charizard.
"Then I was taking a nap." What a coincidence. So was Char. And who likes to sneek around a lot?
"No further questions. You are the culprit."