Is it possible with FFT to find an occurrence of a small wav sample inside of a longer wav, if it is known that that exact sample exists somewhere in the wav (but may be mixed with other sounds)?

*edit*

(after receiving two responses): What if I have a library of all known sounds that can be in the larger WAV and wish to find occurrences of each of them within that WAV? In other words, I know *every* possible sound that can be mixed into the big wav, and wish to find occurrences of them?