Could be a dead mouse/rat inside a wall. If so, it will take about 6 weeks for the odor to stop. Walk around the room and find area the smell is the strongest. This will help you find the source.

Thank you!

I once knew I had a dead mouse in the wall but not the exact location. I got down on my hands and knees and sniffed where the baseboards meet the floor, around the entire room. I found exactly where it was and as luck would have it that spot backed up to a closet so I was able to cut a small hole in the closet wall to get it out. It still stunk pretty bad so I bought a bag of cedar shavings at the pet store and put them in the hole before I closed it up. The cedar shavings helped a lot.

After 32 years in the Cleaning and Restoration business and literally hundreds of pet odor cleaning jobs I’ve learned that ”litter box trained” cats urinate/mark waaaaay more in homes then their owners ever imagine. Countless times we’ve pulled back the carpet in a room where a cat has “never” marked only to find dozens of urine spots.

I‘d suggest purchasing an inexpensive black light and inspecting the carpet in a completely darkened room. Pet urine fluoresces under a black light so you‘ll know immediately if your critter has decided to mark your room.