The off-campus party was sponsored by Gamma Phi Beta sorority, whose on-campus house sits next to the UND American Indian Student Services house. The pictures were posted on the Facebook site of a sorority member. They have been removed, but not before they were found by a member of an anti-logo student group, copied and circulated as a slide show with critical commentary.
The sorority has been placed on probation by its national office and by UND's dean of students office pending an investigation of the discrimination complaint.
Another poster said the party "reminds me of a shindig at [another university] a few years ago. Some brilliant white boys decided to throw a KKK-themed party."
He went on: "I'd like to think the majority of us are respectful, realize the history and proudly wear or use the name and logo. Then you have some absolute idiots go and decide to throw a Cowboy/Indian ... party on a campus embroiled in a debate over the nickname. How stupid can you possibly be? ... If they do retire the nickname in the near future (I hope not), I hope they directly link this event to the ultimate decision."
FYI, racism doesn't necessarily mean overtly attacking or insulting someone. You can be racist if you think an entire race of people is "different," even if you harbor no ill will toward them.
For more on the subject, see Fighting the Fighting Sioux, Team Names and Mascots, and Indian Wannabes.