Four University of Idaho students were killed in "an isolated, targeted attack" with an "edged weapon" like a knife, police revealed on Tuesday.
The students, who were found dead on Sunday in a house near campus, were identified by the Moscow, Idaho, police as: Ethan Chapin, 20, of Conway, Washington; Madison Mogen, 21, of Coeur d'Alene, Idaho; Xana Kernodle, 20, of Avondale, Arizona; and Kaylee Goncalves, 21, of Rathdrum, Idaho.
Moscow police Capt. Anthony Dahlinger told the Idaho Statesman that all four students are considered victims, not suspects.
"We certainly have a crime here, so we are looking for a suspect," he told the newspaper.
No one is in custody but police said they believe there's "no imminent threat to the community."
The fatalities appear to be a "one-off crime" that "was very focused and doesn't involve other students or the public in general at all," Moscow Mayor Art Bettge told ABC News.
It’s believed the crime happened between 3 a.m. and 4 a.m. Sunday, the mayor said. The victims were found around noon on Sunday when officers responded to a report of an unconscious person, according to police.
The weapon wasn't found at the scene, police added.
Police said they're working to "re-create the victims' activities" on Saturday night and early Sunday morning.
Chapin, a freshman, was in the Sigma Chi fraternity and was majoring in recreation, sport and tourism management, university president Scott Green said.
Chapin didn't live in the house but was sleeping over with his girlfriend, Kernodle, according to his mother, Stacy Chapin.
She said a friend who does not live in the house discovered the victims.
"Ethan was well-liked, the light of everyone's life," she told ABC News. "These were all-American kids."
Mogen, a senior, and Kernodle, a junior, were both marketing majors in the Pi Beta Phi sorority, Green said.
Goncalves, a senior, was majoring in general studies and was in the Alpha Phi sorority, Green said. She was the "ultimate go getter" who was "dedicated, outspoken, motivated & full of life," her family said in a statement.
"They were smart, they were vigilant, they were careful and this all still happened. No one is in custody and that means no one is safe," Goncalves' family said. "Yes, we are all heartbroken. Yes, we are all grasping. But more strong than any of these feelings is anger. We are angry. You should be angry."
"And to whomever is responsible, we will find you. We will never stop," the family said. "The pain you caused has fueled our hatred and sealed your fate. Justice will be served."
Green said in a statement, "The university is working directly with those affected and is committed to supporting all students, families and employees as this event undeniably touches all of us."
Anyone with information is asked to call the Moscow Police Department at 208-882-2677.
ABC News' Marilyn Heck and Nicholas Cirone contributed to this report.