For some reason, I feel that perhaps the whole story may not have been disclosed here?
If, however, you were entirely "in the right", and this search was unexpected and unwarranted, I'd urge you to look in that Student Handbook again to review the policy regarding dormroom searches. Most campuses will NOT permit a search without the student actually being physically present at the time -- furthermore, many campuses actually are required to give ADVANCE NOTICE (often more than 24 hours) before conducting a search -- unless, maybe, a "clear and present danger to residents or staff" was known to exist. It seems highly irregular that a Resident Advisor (another student?) would be permitted to enter a student's locked private room to rummage through his personal effects without oversight of any kind. Was said search conducted solely at the unsupervised RA's discretion? Without any witnesses present? And items were then removed from the room by this sneaky degenerate? Then -- based solely on said RA's unsworn testimony, with no evidence -- or even a Polaroid of said evidence -- being in the possession of Administrators, eviction proceedings are finalized and an armed raid at 2300 hrs is conducted to escort the student from the premises in the middle of a rainstorm with no criminal charges being pressed and no means of alternate housing made available? I dunno, but my BS detector's going off . . . even though I'm familiar with administrative incompetance, this seems a bit TOO unbelievable.
Unless there's certain other issues that have not been brought up, I would definitely pursue a Civil lawsuit versus both the University and the RA personally. If your story is accurate, that RA is quite possibly guilty of "malice", "filing a false report", "intentional infliction of mental pain and suffering", and just abusing his position of authority in general. At the VERY LEAST, he should be removed from his position of authority, and the campus should immediately institute a policy where such random searches -- if permitted -- must be conducted under the supervision of a staff member who actually seems to have a brain.
Talk to a sue-happy lawyer who knows his stuff. Write a letter to the editor of the local newspaper. Talk to the editorial staff of the campus newspaper. I have trouble believing that such a thing actually happened -- a decorative wood letter opener is NOT a knife, and sending the police to throw you out in the street in the middle of the night seems a bit extreme, even for having a samurai sword hanging on your wall! This doesn't make sense. . .