Can someone help me on attic fans?

I know this is heat and air forum, but i didnt find a place for attic fans.

Okay my mom calls me at work, loud screeching coming from attic. the neighbor came out because she also heard it.

So i go home to check and it stops before i get there,

i call my dad and he said it might be attic fan so he comes over and disconnects it but at that time the fan is running and no noise, maybe it had noise trying to start? but its not making it now.

So does anyone think this noise is coming from that? is it a belt? or bearing?

okay i just brought the house- I have home warranty-they cover attic fans, but not belts. so do you think its the belt or is the fan going? because i dont want to spend $100 for home warranty contractor to come out and tell me the belt is not covered. and lose $100 where i can get someone to replace it myself.

Any thoughts to what it is?

any help is appreciated. first time homeowner.

Kim