2004 Honda Accord Rear window

This evening, as I started the car, I just noticed that one of the rear windows wind down by itself. Attempt to wind it up and down proved abortive as it remained down with about 6 inches coming out. The I turned off the engine came out of the vehicle then used the key to lock the window and it actually locked it. But immediately I turned the ignition ON it wind down again.

Then after driving for some time, I tried winding it up and it responded but after some time by itself wind down again.

What could be causing this?

Thank you