re: Construction/ Home question. Help with fireplace/mold smell situation

This is a shot in the dark, but the wax ring on the toilet will give off an odor. That's a start. But if the cabinets inside, the next thing, look at the cabinets, you could have a pin hole leak, drip behind the wall. You could remove the back of the cabinet, remove the Sheetrock. At least get a look.