Here are some good videos on youtube to watch 

http://www.youtube.com/watch?v=EECBjnasoEk ray haffner has rough strong has hands when they show the suspects remember he was the only one they showed lifting weights. If you lift weights all the time you will develop rough strong hands. Weird that they showed him lifting weights. Red john drinks tea with his left hand and on the cell phone with the left hand. 

http://www.youtube.com/watch?v=jzCBXX58tAg

http://www.youtube.com/watch?v=XDWPD8lvt9Q good one to watch too even though it has spanish 

http://www.youtube.com/watch?v=liUBD1ck_Lc with some music lol