University of Michigan graduate students Ran Xu, 22, and Zhangqin Xie, 22, were killed in a Saturday morning crash on I-75 north in Arenac County, Michigan State Police Trooper Jesse T. Diaz said this afternoon.

Diaz said the cause of the crash is still under investigation, and the vehicle is being inspected. He said neither alcohol nor text messaging were factors in the crash.

Xu was driving the vehicle, and Xie was the front-seat passenger. The three other passengers in the vehicle were injured: Chang Gong, a 23-year-old U-M graduate student; his girlfriend Wenting Cheng, a 22-year-old U-M graduate student; and MSU graduate student Linling Cai, 22.

All five of the people in the vehicle were international students from China. Diaz said Xie would have turned 23 on Sunday.

Diaz said Gong suffered a dislocated hip, but is expected to recover, Cheng will require surgery on her leg, and Cai has a broken arm.

According to WDIV in Detroit, the students were believed to be on a tour to see fall colors. Inside the vehicle, troopers said they found a map to Tahquamenon Falls State Park, and attached to that map were hand written directions to nearby hotels, WDIV reported.

The Lansing State Journal reports that Cai teaches language and culture in the Chinese immersion program at Lansing's Post Oak Magnet School.

Heather Lockwood is a reporter for AnnArbor.com. Reach her at heatherlockwood@annarbor.com or follow her on Twitter.