My Hotpoint dryer's tumbler does not spin?

The dryer was working properly then all of a sudden it stopped spinning. I checked the belt and it is just slightly narrowed by like one or two millimetres but not all around only in one section and it is not cut. When I spin the drum with my hand it spins. The motor seems not to rotate but makes some noise as if something is stopping it from rotating. Everything else including the heater seems to work as it lights up and get hot.
What could be wrong?