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)
“I meant to behave but there were too many other options.”
"If you run into an asshole in the morning, you ran into an asshole. If you run into assholes all day, you're the asshole." ~Raylan Givens, Justified