Starter motor keep on going after tuck is on.?

I starter my toyota tacoma, but the starter motor keep on going even after the truck was on. I try turning it off but it would not go off until I disconnected the Battery. I tap the Starter a few times disconnected it and connected it back. After I did the problem went away, but when I turned on the truck there was a weir grinding noise does. Does anybody know what I can do about it? Do I have to change my starter?|||Sounds like a bad starter to me. The grinding noise you heard was this during initial start? Cause a starter will grind if its turned while already on.|||Sound like the solenoid is sticking, you can pull it out and have it bench tested at an auto parts store.|||Sounds to me like the starter drive is sticking and not retracting properly once the engine starts. Does the ignition key spring back to the %26#039;on%26#039; position when you release it? If that is fine, it could be the starter solenoid going bad. And now that you have the grinding noise, the starter drive or flywheel teeth are probably damaged.