It is unfortunate that they are no longer on that campus.
I recommend contacting the university to see if they have any records of ANYTHING pertaining to the organization or some of the members whose names you remember.
I assume it was a local so there wouldn't be a larger entity to contact. (There's another Sigma Phi Nu that was founded in 1996)
"Men are from Earth, women are from Earth. Deal with it." ~ George Carlin
"But I have wisely been reminded that things are not always clear in print and you do have to hit the nail a bit more squarely on the head if you want to be sure to be understood."
~ Yoda aka DuBaiSis