My reasons for suspecting him are:
1. He has a tall, muscular build. He looks like he is very "thick." Not like fat, but like he is very dense.
2. He often licks his lips.
3. He stresses his "s."
4. His teeth seem to be a little sharp.
5. He carries himself kind of stiffly.
6. If you blend a Reptilian face over his own, it isn't that hard to see.
These are all based on physical observation. I could be completely wrong. However, he strikes my intuition as strange.
In this picture, his pupils appear to be slitted. He had a general "frog-like" appearance.
He is usually taller than everyone else.
His pupils have luminescence and there is an orb near his ear. (This may be a camera artifact. I know that orbs are sometimes just dust or moisture.)