here's more. >> reporter: the chant is so offensive, it's hard to listen to. sae sae, this chapter at the university of oklahoma is on their way to a saturday night party celebrating the fraternity's founding. the video was sent anonymously to a campus group called "unheard" that works to fight racism on campus. on sunday they posted it online. unheard's co-founder spoke to cnn. >> this chant wasn't something we learned overnight. it was well known, well versed that everybody on that bus proudly clapped at. >> reporter: the outrage was universal. by sunday night the sae national headquarters suspended its ou