It's not the smell of death, though-- it's certainly mildew. Like as clothes warm up on the body it gets worse, or if you shove your face in a towel while drying. I *thought* maybe it was leaving clothes in the washer overnight and transferring them to the dryer, but as I suspected it, I both rushed to get things to the dryer and smelled the clothes coming out of the washer and didn't smell it.
I have had rodents of unusual size die under my house and in a wall. My car once broke down in the mountains by a select piece of former deer. I know this smell. If it was that smell, we would have burned the clothes or maybe the whole house down by now. ;)