Can a u.s. marshall enter and search someone's house without a search warrant, looking for someone that does not even live at that house?

With the Patriot Act it pretty much does bypass the search warrant and they do seem to use that as their back up when questioned on it.

There are other types of warrants.
warrant legal definition of warrant. warrant synonyms by the Free Online Law Dictionary.
Did he have any other type of warrant? If he did I think the answer might be yes depending on the circumstances and details

Hello TS:

It's not quite as simple as that. In general, no he can't. However, if he didn't find anything incriminating and you aren't being charged with an offense as a result of the search, then it really doesn't matter whether he had a warrant or not.

Certainly, complaining about him ISN'T a smart thing to do...

excon

Normallyi no, but ** wait, did I hear someone calling for help in that house?
Do they have a reason, or did someone give them permission to enter the home,