MOSCOW, Idaho (NewsNation) — Officials investigating the stabbing deaths of four University of Idaho students at a house near campus asked for patience after a week passed with no arrests. Residents of the small college town remain on edge and concerned about their safety.

The campus was quiet Monday, as many students have already left and the university expects some won’t come back.

According to the residents, Moscow has always been a quiet, safe community — but that bubble of safety has been popped.

“[It’s] concerning, for sure,” one Moscow resident told NewsNation’s “Rush Hour” on Monday. “Trying to make a concerted effort not to let ladies walk home alone or anything. It’s not expected ’cause this is such a small town, seems pretty quiet.”

During a news conference on campus Sunday, authorities said they have no suspect or weapon in the Nov. 13 killings that shook Moscow, a town of 25,000 residents in the Idaho Panhandle.

Moscow Police Chief James Fry said authorities have received nearly 650 tips and conducted 90 interviews so far. Police have also requested businesses and residences in specific parts of the city to share with them footage recorded between 3 and 6 a.m. on the day of the killings.

All four victims were members of fraternities and sororities: seniors Madison Mogen and Kaylee Goncalves, junior Xana Kernodle, and freshman Ethan Chapin. The women were roommates and Chapin was dating Kernodle.

“Nothing we can do can will bring back these lives, but we have an absolute commitment to working together to solve these senseless murders,” said Idaho State Police Col. Kendrick Wills.

Police said the victims were found on the second and third floors of the six-bedroom home but declined on Sunday to say specifically on which floor the individual victims were found.

Authorities Sunday said they were each stabbed multiple times, and that some had defensive wounds.

Police said Chapin and Kernodle were at Sigma Chi house on the University of Idaho camps and returned home around 1:45 a.m. on Nov. 13. Police said Mogen and Goncalves were at a bar called The Corner Club in downtown Moscow, left the bar and stopped at a food truck, and then also returned home at about 1:45 a.m.

Mogen and Goncalves also made multiple calls that night. Police said Goncalves made several calls to a longtime boyfriend with whom she recently split up. Goncalves family said that’s not unusual for their daughter and the ex has nothing to do with the murders.

Fry said Sunday that police believe those calls have no connection with the killings.

Another person wearing a hooded sweatshirt and seen in a video at the food truck near Mogen and Goncalves shortly before they returned home is also not involved in the crime, police said. Additionally, police said, a private driver who gave Mogen and Goncalves a ride home was not involved in the crime.

Police said two other roommates who were in the house on the night of the killings had returned home at about 1 a.m. and slept through the attack, waking later that day. Police said one of their phones was used to call 911 from inside the residence at 11:58 a.m. Police on Sunday declined to say who made the 911 call but did say additional visitors had come to the house that morning.

Police said the victims were found on the second and third floors of the six-bedroom home, but declined on Sunday to say specifically on which floor the individual victims were found.

Police have said evidence leads them to believe the students were targeted, though they haven’t given details and declined to do so again on Sunday. Investigators say nothing appears to have been stolen from the victims or the home. Police have said there was no sign of forced entry, and first responders found a door open when they arrived.

“Based on the evidence of the scene and based off of what we believe that we know — and, again, this is from specials who have been inside that location — is that it does appear to be targeted,” Aaron Snell of the Moscow police told NewsNation’s “Rush Hour” on Monday.

Tracy Walder, a former CIA officer and FBI special agent, joined NewsNation’s “Rush Hour” on Tuesday to shed light on what could possibly be leading officers to believe the attack was targeted.

“A key piece of evidence that would point them in that direction would be a note, saying ‘I have some sort of vendetta against one of the victims that are inside of this home,'” Walder said.

“That would tell police this is probably contained to this scene. If there’s a note or some kind of message written in the home — that’s what would mostly tip them off.”

In continuing, however, Walder expressed that she felt the police department’s reporting was “problematic,” as they have been “conflicting.”

“First, they say this is a definitely a targeted attack and that there’s no need for the public to worry. Then they asked the public to remain vigilant and now they’re sort of walking back whether or not it was … targeted … It was perhaps a bit premature for them to say that,” Walder said.

Investigators say they do not believe the two other roommates were involved. One of them found one of the victims, initially believing they were passed out and called a friend before calling 911.

Moscow hasn’t had a murder case in about seven years. Until a suspect is found, the Moscow community won’t rest.

“There’s a lot of anxiety and a lot of people not knowing what to do to keep their friends and family safe,” one student told NewsNation.

On Sunday, students and residents expressed concern about a lack of details from police, who initially said there was no danger to the public but a few days later walked that back by acknowledging they couldn’t say there was no threat.

“We know that people want answers — we want answers, too,” Idaho State Police Col. Kedrick Wills said. “Please be patient as we work through this investigation. We owe this to these young kids. To these young adults. We owe it to them. And we’re absolutely dedicated to make sure that that happens.”

Police previously seized the contents of three dumpsters to locate possible evidence. But Sunday, Moscow Police Capt. Roger Lanier said “nothing of note was discovered.”

Police on Sunday also asked the public to avoid rumors about the killings and get their information only from official sources. Police have previously said online reports of the victims being tied and gagged are not accurate.

The Associated Press contributed to this report.