1996 mustang GT ignition problem

Okay so here is the story. I was driving out of town with a friend of mine. Stang started fine, ran fine and all a sudden I forgot to check my oil so i pulled over, and i turned the key back to shut it off and the stang would not shut off so I drove back to my house and i pulled off the hose to the throttle body and I put my hand over the throttle body to kill the engine. I left it home that day. next day I pulled the shrouds off of the steering column, un bolted the ignition switch. and I was able to use my stang from there but not by turning the key. so what could this be. I cannot see anything other than something could be broken somewhere between the ignition lock cylinder and the ignition switch.
I would appriciate some info guys because i really need this car up and going.

thanks,


Randy