One of my rooms in my house smell weird once and awhile?

Ok, first I bought a foreclosed home that is three bed and one bathroom. It has natural hardwood floors and it is in good shape. But before moving in, one room has a distinct odor of urine or shrimp smell. Well after intense cleaning and moving in, my family have enjoyed the house. But that smell comes and goes from time to time, and it comes potent. I have scrubbed and washed the floors very well, but again that smell comes and goes. Again this home has natural hard wood flooring, and I'm a new homeowner so any suggestions would be appreciative.