My late father in law was a homocide detective for LAPD and transported a number of murder suspects back to LA. There were some great stories - like the guy from an Alabama prison who was relieved to be extradited because he was looking forward to real meat in the LA area prisons (as opposed to what they could catch and kill and cook) or the time they got fogged in at LAS and had to take the suspect to LAS jail for the night until the flight out the next morning and they got to have some fun for the night.

I've been on a few flights where they are transporting someone and they typically take the back row. I recall being on an RJ and having to use the LAV and having the handcuffed pax leer at me but I knew I was safe