I recently bought a 2010 Dodge Challenger with a Pioneer avic x930bt already installed in it. Everything was fine for the first few weeks, but last week I went to start the car only to find the battery dead. [This is not my daily driver, it had sat for about 2 weeks.] I didn't think much of it as it had an older battery and hadn't been run. 

I jumped the car and everything seemed to be fine. It didn't register until later that the radio had come on when the cables were connected without the key on. When I went to shut the car off, same thing, the radio stayed on after the key was removed and the doors had been opened. 

I had played with a bunch of the settings trying to get it set the way I wanted the last time I had run the car. Could I have accidentally done something that bypasses the ignition signal wire, or should I be looking for a "mechanical" problem in the wiring. Being used, I don't have manuals, or any idea on the install. 

Any help/guidance is appreciated. 

Here's a link to installation and user's manuals. AVIC-X930BT Manuals

I don't think there's any settings that could cause this. Assuming it was installed correctly (2 separate circuits and fuses - one always hot and one hot with the accessories) then it might be something wrong with the car's ignition switch.