George, a pharmacist, lusted after Bree once she ended their affair together and became jealous of her husband Rex. So he tampered with Rex's prescription drugs by replacing his heart medication with placebos which led to Rex's death. He also beats up and attempts to kill other people who look like they are trying to come in between him and Bree. He also drugged Bree at one point and was seriously considering taking advantage of her. He eventually proposed to Bree and pressured her into marrying him. After the engagement he became increasingly possessive of her, and increasingly violent.
The riot against the ex-convicts home which Paul Young set up. Including having Susan trampled, Lee and Bob trapped in a car which is being beat up, Juanita, a child screaming in terror whilst in the car, and the good old fashioned clustrophobia of being pushed along by masses of people. For parents, there is also Juanita beng lost in the mob.
When a new neighbor moves in Wisteria Lane along with his sister, Lynette soon discovers that he keeps a lot of pictures of his former students in his basement. Troubled by his behaviour and persuaded that he is a pedophile, she warns her neighbors. However, they became violent, and began to harass the guy so much, that his sister has a heart attack, and dies. Lynette is devastated by grief, and go see him to apologize... Only for him to thank her. Turns out his sister only viewed the good in him, and was acting as his Morality Chain. With her gone, he is free. Lynette is paralyzed in Fridge Horror, realizing that she just "freed" a pedophile. The guy moves out of Wisteria Lane, free to do what he wants. One of the few examples of Karma Houdini of the show.
Granted, it is POSSIBLE that he did this to get back at her for being the catalyst of his sister's death and him having to pack up and move. The point of it is that we simply do not know. Which, in some ways, is worse than confirmation.