OT Handymen/Pest Control

I have an awful smell coming from my laundry room. My initial thought was that it could possibly be some mildew built up in the washer. Ran a cycle of bleach and the smell persist.

I smelled the dryer outlet and nothing, the washer drain and nothing (dumped a little bleach in there just to be sure.).

I have narrowed the smell down to the exhaust fan in the room, the smell is eitheihg coming from the “attic” space above or down from the exhaust vent duct. I find it highly unlikely that it’s from the “attic” space because that is just space between floors. The roof is too high and has too much pitch and I don’t have the resources to get up there and check the exhaust vent.

It smells like something dead.

Any advice from the OT ballers? I’m not even sure who I’d call to investigate.....pest control, handyman, A/C service company, duct cleaning, etc.

I just put the house on the market to sell as I’m building a new house. I’m really hoping this is a simple fix.