It's always the ones you suspect the least. Ned Flanders is the perfect neighbor. He's kind, he's considerate, and he'd do anything to help you in a time of need. He wouldn't secretly be manufacturing drugs and killing people - would he?
We only ask because he looks so much like Bryan Cranston, and you know who Bryan Cranston is. Say it quietly, but he's Heisenberg. Ned, what do you really have in your basement? Are you the one who knocks?