Campus police at Indiana University have stepped up security around campus since the fifth sexual assault was reported on campus this semester.
Late Friday night, a 19-year-old student was running near Walnut Grove and McNutt Quad when she was grabbed from behind, the Indianapolis television station 6 News reports.
The woman said her attacker threatened her to be silent.
"Don't say anything. I have a knife," he said, according to 6 News.
Officials across the country believe sexual assault is the most underreported crime. At Ball State, where 60 percent of the population is women, only one forceable sexual offense was reported in 2008 and one in 2009. Four cases of sexual assault were reported in 2007, according to the Campus Security Report.
Programs like Rape Agression Defense help women learn how to defend themselves from such attacks. For more information about RAD, students can contact Sergeant Kent Kurtz at 765-285-1111.