If you are doing an Audio type search, then with LW 5 only audio search results should return in any case. If you're doing an any type / general search then all types of files will return in the search results. So make sure you click on the Audio type search before you search. You can also use the advanced search feature from top of the Tools menu.

Warning: If you see audio files which show no bitrate, beware of them. There is a reasonable chance they are fake. However you won't see bitrate unless you view search results in Classic mode & enable Bitrate column from heading bar.