I have a simple question.. If a U.S. citizen enters the U.S. and is stopped in airport customs in the U.S. and lets say is bringing school certificates, pictures, etc of another person NOT on the flight... Then can INS investigate the owner of these certificates?

INS won't investigate it since there is no INS.

CPB or ICE may have some interest.

Why would you show them the documents of someone else? If you stick it up their nose, yes, they might look at them.

K sorry No clue what cpb or ICE is... Please explain... Let me give you some more info, A nephew of a friend came here to the U.S... He was bringing some paperwork of my husband's with him as a favor. He got stopped by customs and from what I understand they searched ALL of his belongings... He didnt show them the certificates.. They found them and asked the kid( 18yrs ) why he had them, he replied as a favor for his friend... They told him that they would photocopy the certificates and then investigate the owner of them... Can they do this and why would they have the interest to do so? Thanks

Customs & Border Protection (CBP)
Immigration & Customs Enforcement (ICE)

Probably - but one hopes they have better things to do.

Yes they can...

They would do so in the interest of Homeland Security or for the prevention other similar potential criminal activity.

ARQU