Don't be so quick to rule him out, ladies.
While Chi Delta Theta is an Asian-American sorority based in California, there is a Chi Delta Theta Fraternity out there...and I found their website. Because of some of the things I found on their website, I thought that it'd be smart NOT to post the URL here and I kindly ask that you not post it also if anyone comes across it.
From what I read on that website, Chi Delta Theta Fraternity is an Internet-based organization. Those interested can fill out an application online and the brothers then schedule an appointment to meet with you.
So, chances are this guy you met online is a "frat boy", but just be careful with ppl you meet online.
Also, many organizations share letters. I know that there was a post about this somewhere.
For example, Phi Sigma Rho is a local sorority on my campus...but it's also a *NATIONAL* social sorority for engineering women!