Thread: starter motor comes on by itself

We driving home from a picnic yesterday and noticed it just came on puller over turned the key off and the engine was cranking over all bt it self with the key off the it dropped off and was ok. So I had a look found no melting wires and thought it was the starter.
Last night at 4:30am it started cranking all by it self again.
I tookthe starter out cleaned it all up and couldn't find anything wrong with is.
I am thinking it must be a short between a live feed and the power from the starter relay behind the fuse box and the starter.
I thought about the circuit from the switch to the relay but it has no power when the car is off.
Anyone had this issue?
Any ideas?
I don't think it possable for the starter to cause this issue.

Starter motor solenoid? The contact bar in the end cap may have come loose or the return spring is broken. Same applies to the key switch. Broken spring or terminal?