Surrounded by photos of her daughter in her living room, Holly Comstock talked Monday about the three unanswered text messages and the unreturned phone call she made to her 18-year-old daughter, Heather, the day before.

It had been more than three hours since she heard from the University of Michigan freshman, who was heading home to Okemos with friends.

"I called my husband and said, 'It's about 6:30. I don't get it,'" Comstock said. "She always calls me."

This time, there would be no call from Heather.

Her daughter, Heather's boyfriend, Matthew Kolstoe, 18, also of Okemos, and Sarina Seger, 18, of Williamston, died about 3:30 p.m. in a two-car crash north of Ann Arbor on U.S. 23 in Livingston County. They were on their way home after attending festivities in Ann Arbor surrounding her school's annual football game against Michigan State University.

Authorities said the Toyota Prius in which they were riding crossed the median and slammed into an oncoming Chevrolet Blazer, killing two adults and injuring three children.

The victims in the SUV were identified as Cynthia Skutt, 62, and Alfred King, 56, of Fremont, Ohio.

Another 18-year-old in the car with the teens was in critical condition, Green Oak Township Police Chief Robert Brookins said.

Deputy Okemos Schools Superintendent Patty Trelstad said an emergency staff meeting was held early Monday at Okemos High School. District officials told teachers about the crash and that counselors would be made available to staff and students. Teachers shared the news with the 1,400-member student body.

"Most of the faculty was OK," Trelstad said. "Some students asked, 'Why?' and 'How can this happen?'"

Trelstad said she didn't personally know the students but was told good things about them.

"They were great kids and close friends to one another," she said.

Holly Comstock, wearing a gray pullover with Michigan written across the chest, told The Associated Press that Heather's plan was to return to Okemos on Sunday evening so she could pick up her car and go back to Ann Arbor for Monday classes. She was majoring in molecular biochemistry, stem cell research and organ transplant engineering.

Holly Comstock learned about the fatal crash about 9 p.m. Sunday from a friend of the Comstock and Seger families.

School officials were planning to contact the parents of the students who were killed to talk about ways the school could remember them, Trelstad said.

"Okemos is a fairly close-knit community through the schools," she said.

Brookins said Monday that police don't know the exact cause of the crash.

"We have a whole lot of reconstructing to go through," he said.