Starters keep burning up in my car.. randomly continues to run when i turn my car off.

I bought my Sebring a month and a half ago and i have
already had to put 3 brand new Duralast starters in it. Ill be
driving and then ill randomly hear a loud squeal/screeching
sound that continues until i pull over and turn the car off..
when i turn the car off, i hear the starter still going (like its
trying to start the car) but the key is in the off position. Its
happened 5 times.. twice it randomly stopped before the
starter gave out but the other 3 times the starter burnt up.
The last time the starter burnt up (a few days ago) there
was also a terrible smell and smoke coming from under the
hood and even into the car. It smelt like an electrical fire.
And then of course.. that starter completely burnt up again.
What could be causing this? I need help.