Warrent for one thing, charged for another?

the secret service recently served a warrent for my apartment while i was away at class. the copy they left with my roomate states no clear reason for the warrent only "see attachment" which there was none. after getting the run around trying to find out why my computers and documents were taken away the case agent stated that it was suspected credit card fraud. now i have never stolen a credit card nor have i ever used a credit card that was not mine so im confident that no charges relating to that will be persued. however, if the secret service finds other "illegal" material from the search not relating to credit card fraud, can they charge me with it?
the warrant can be seen online if need be but there is no real information on it except for a list of items they took and a few phone numbers. no real helpful information in my opinion.

users

has anyone else ever used your computer? is your phone line accessable from the outside of the building/other rooms? did they look through your fiancial files and request your wallet?

i was not there at the time, only my roomate. no no one else has used my computer (to my knowledge) and no one has access to my phoneline except me and my roomate who i trust. im just wondering if they can charge me with anything they find that is unrealted to the warrant they served.

The answer is yes, they can charge you with any crime they have probable cause to believe you committed. However, if the search was not legal, that is, not justified by a warrant based on probable cause, then whatever they found in the search would be suppressed, and they could not charge you with what they found.