Toyota Repair: engine, toyota corolla, starter problems

Question
I have a 97 Toyota Corolla, automatic, about 103000 miles on it.  Just last night, I turned off the car, took the key from the ignition and the car kept running! I could not get it to stop until I (eeeeeeeek)cranked the key back to the start position and caused it to grind and stop.  There is an alarm on the car also that sets after 30 seconds (automatically) and that was acting weird also(it wouldn't recognize that the car was still running and was setting as if the car was off).  Do you know why the car would act up like this? I have been in possesion of the car for about 9 months and I have not had any problems like this before.  Thanx for any info!

Answer
Starter problems are common on corollas, it sounds like the starterengaged while the engine was still running and when the key was turned off the starter kept turning the engine over going by your description of what happened, the best recommendation I can give is to replace the starter.