WEST LAFAYETTE, Ind. (AP) — A Purdue University student was arrested Wednesday in the killing of his roommate in their campus dorm room, authorities said.

Ji Min Sha, a 22-year-old cybersecurity major from Seoul, South Korea, was arrested on a preliminary murder charge in the killing of 20-year-old Varun Manish Chheda, a 20-year-old data science major from Indianapolis, Purdue Police Chief Lesley Wiete said.

Tippecanoe County Coroner Carrie Costello said an autopsy determined that Chheda died of “multiple sharp-force traumatic injuries.”

Wiete said Sha, who goes by the nickname “Jimmy,” called police at around 12:45 a.m. “alerting us to the death of his roommate” in their first-floor dorm room on the campus in West Lafayette, which is about 65 miles northwest of Indianapolis, Wiete said.

He has not been formally charged. Wiete said investigators don’t know why Chheda was killed, but they think he was awake at the time.

“I believe this was unprovoked and senseless.” Wiete told reporters outside the residence hall.

Students living near the crime scene were moved to other rooms, and the university provided counselors for those who need it, Purdue spokesman Trevor Peters told the (Lafayette) Journal & Courier.

Purdue President Mitch Daniels said in a statement that “this is as tragic an event as we can imagine happening on our campus and our hearts and thoughts go out to all of those affected by this terrible event.”