BOISE, Idaho >> The killer — or killers — who stabbed four University of Idaho students to death remained at large Tuesday, prompting many students to leave the campus in the idyllic small town despite police assurances that there was no imminent risk to the community.

So many students had left the scenic tree-lined campus in Moscow, Idaho, by Tuesday that university officials said a candlelight vigil scheduled for the next day would instead be held after the Thanksgiving break.

The students, all close friends, were found dead in an off-campus rental home around noon on Sunday, and officials said they likely were killed several hours earlier. Latah County Coroner Cathy Mabbutt told the Spokane, Washington-based television station KXLY that her preliminary investigation showed the students were stabbed to death. There is no indication that substance use was involved in the deaths, Mabbutt said.

The Moscow Police Department has not said whether investigators have identified any suspects, but maintained in a statement that the killings came in “an isolated, targeted attack and there is no imminent threat to the community at large.” Police also said evidence from the scene indicates there is no broader risk, but provided no information about that evidence nor why they believe the victims were targeted.

Latah County Prosecutor Bill Thompson said he understands that the police claims that the public isn’t at imminent risk seems contradictory to the facts that have been released so far about the killings.

“Obviously, there’s no way police can say that there’s no risk, but what they’re seeing indicates that there’s not a risk that this person will randomly attack people,” Thompson said, noting that it’s also not yet clear if it was one attacker or more.

“I don’t think they’re going to foreclose the possibility that it could be one or more people, but right now they don’t know who is responsible,” Thompson said.

The police department said investigators were working to establish a timeline of the victims’ activities before they were killed. That includes reviewing video from a Twitch livestream that showed two of the victims chatting and getting a late night snack from a food truck in the hours before the slayings, said Thompson.

“They’re in the process of identifying the other people who were there,” at the food truck, Thompson said, “and what sort of contact did they have.”

Autopsies scheduled for Wednesday could provide more information about the slayings.

Investigators were “following all leads and identifying persons of interest” in the case, the police statement said.

Police responding to a report of an unconscious person at the home Sunday discovered the students’ bodies. The victims were identified as Ethan Chapin, a 20-year-old from Conway, Washington; Madison Mogen, a 21-year-old from Coeur d’Alene, Idaho; Xana Kernodle, 20, from Avondale, Arizona; and Kaylee Goncalves, 21, from Rathdrum, Idaho. Authorities have not described which of the victims lived in the home.

Kernodle’s sister, Jazzmin Kernodle, wrote in a text to the AP that her family was confused and anxiously waiting for updates from the investigation.

“Xana was so happy and loved, and it breaks my heart,” Jazzmin Kernodle wrote. The other students were also amazing people, she said, and her sister was lucky to have them in her life.

“She was so lighthearted, and always lifted up a room. She made me such a proud big sister, and I wish I could have had more time with her,” she wrote. “She had so much life left to live.”

Photos on Instagram show the four as close-knit, longstanding friends. All were members of sororities or fraternities. Kernodle and Chapin were dating.

In one post, Kernodle wished Chapin a happy birthday, writing, “life is so much better with you in it, love you!” The caption was accompanied by a photo of Chapin in a chef’s hat with Kernodle on his shoulders and wearing mouse ears.

Several weeks ago, Goncalves posted a series of photos showing her and Mogan growing up together. “I wouldn’t have wanted anyone else to be the main character in all my childhood stories,” she wrote.

“I love you more than life! My best friend forever and more,” Mogen replied.

Another photo, apparently posted hours before they died, showed the four smiling and posing, seemingly carefree, along with two other friends. Chapin had his arm draped over Kernodle’s shoulders, and Mogen was perched on Gonclaves’ shoulders.

“One lucky girl to be surrounded by these people every day,” Goncalves wrote.

Signs of the community’s grief and uncertainty were scattered throughout the small farming town on Tuesday. Moscow has about 26,000 residents but that population swells by about 11,000 when the students arrive.

A makeshift memorial with flowers, candles and notes was set up on a table in front of the Mad Greek restaurant in downtown Moscow where Kernodle and Mogen had worked. Four white pillar candles, each inscribed with the name of a slain student, burned in the center of the table.

The restaurant’s owner wrote on Facebook that Mad Greek would close for a few days so staffers, friends and family could grieve “this incredible loss.”

“Xana and Maddie have been servers here for several years and brought so much joy to our restaurant and all of those they encountered,” the owner, Jackie Fischer, wrote. “You will be greatly missed. Thank you for being a part of our family/team, and for helping me so much over the years.”

A flag flew at half-staff before the Sigma Chi fraternity, where Chapin was a member, just a short walk from the home where the four died.

The six-bedroom rental home remained surrounded by crime scene tape on Tuesday but had little sign of activity inside. A Latah County Sheriff’s deputy stood guard near the driveway, and Idaho State Police officers were also at the scene.

Moscow police Captain Anthony Dahlinger said police were “trying to identify a suspect” but would not say if investigators had anyone in mind.

“These things are dynamic and constantly changing,” Dahlinger said.

The University of Idaho canceled classes on Monday and said additional security staffers would be available to walk students across campus. Still, the lack of arrests and scarcity of information about the deaths prompted many to leave days before the Thanksgiving break was scheduled to begin.

The students who remained showed little sign of apprehension.

“I feel pretty safe,” said student Nicole June on Tuesday. “I believe the police can do their job.”

Nathan Lannigan, 18, said he was surprised with reports that there is no ongoing threat since a perpetrator has not been captured.

“That’s a quick judgement, I think,” Lannigan said.

In a Monday memo, University of Idaho President Scott Green urged university employees to be empathetic and flexible, and work with students who wanted to spend time with their families.

“Words cannot adequately describe the light these students brought to this world or ease the depth of suffering we feel at their passing under these tragic circumstances,” Green wrote of the slain students.

The university said Chapin was a freshman, and Kernodle was a junior majoring in marketing and a member of the Pi Beta Phi sorority. Mogen was a senior also majoring in marketing who belonged to Pi Beta Phi, and Goncalves was a senior majoring in general studies and a member of the Alpha Phi sorority, the university said.