Anyone really serious about finding anything needs to use Find File. It dates from '08 and, needless to say, has long since ceased to be supported, but it's free and still compatible with OS X up to v11.1.2 dev. prev., nevertheless. FF found MacKeeper infecting my iMac after both DetectX and Malwarebytes found no trace of it. Naturally, FF doesn't remove what it finds, but there's nothing keeping you from DIY.
This is *not* to say that DetectX and Malwarebytes are not valuable apps. They are, since, in order to find anything using FF, you have to *specify* what it is that you're looking for. It will find "MacKeeper," but it won't find "malware" or "badware." It goes without saying that FF is good *only* for *double-checking*, after you've already used a more-general, anti-malware tool, such as DetectX or whatever.