What's worse than a dozen grinning frat boys chanting a racist song on a bus in Oklahoma? A literal boatload of frat boys teaching each other racist chants — at a leadership event! Oklahoma University President David Boren announced Friday that after conducting interviews with 160 people, university officials discerned that the song was taught on a cruise sponsored by the fraternity's national organization four years ago, and attendees brought it back to Oklahoma, NewsOK reports. "The matter cannot be closed, in our view, until the culture at the national level is addressed," Boren said at the press conference announcing the result of the school's investigation. OU shuttered its SAE chapter and expelled two students after video surfaced of fraternity members singing the shockingly racist chant, which made references to lynching and used racial slurs. Other members of the fraternity will face less severe punishments than expulsion, such as community service, according to the Associated Press. SAE's national organization had disavowed the actions of the Oklahoma chapter. In a statement released after two Oklahoma students said that they were "taught" the chant, SAE leadership said in a statement, "the national fraternity does not teach such a racist, hateful chant, and this chant is not part of any education or training," It also announced plans to eliminate racism in its chapters in the wake of the video. The school's report found that the chant had become part of the "institutionalized culture of the chapter" at the University of Oklahoma, and that there were high school students at the fraternity before the events filmed on the bus, and that those children were "exposed" to the virulently racist chant. A separate video has since surfaced of the frat's "house mom" chanting racial slurs, too. At a press conference on Wednesday, Levi Pettit, one of the two frat members expelled for the chant, apologized and asked for forgiveness. The full OU report is availabe via local Oklahoma news station KFOR.