FIRST ON FOX: MOSCOW, Idaho – Investigators returned to the Idaho home Friday where four college students were stabbed to death in their sleep earlier this month, collected several small bags of evidence – then met up with the Latah County prosecutor inside police headquarter after sundown.
Aaron Snell, the communications director for the Idaho State Police, told Fox News Digital downplayed the significance of the late meeting and said investigators had been routinely putting in long hours.
"The DA has been present throughout as a resource," he said. "We continue to work after hours. The DA has been here daily."
That included Thursday, which was Thanksgiving, when Latah County Prosecuting Attorney Bill Thompson returned to the police department around 2 p.m. and left around 10 minutes later.
On Friday, he was inside with investigators, including several who had returned to the house earlier in the day, for about an hour.
In the late afternoon Friday, police and members of the FBI first looked outside and walked up the hill behind the home, which is built into a slope and stands three stories tall.
Next they came back down and were seen putting on protective covers over their shoes and returning inside the home on King Road, which had been untouched for days, according to a deputy standing guard Thursday morning.
Kaylee Goncalves, 21; Madison Mogen, 21; Xana Kernodle, 20; and Ethan Chapin, 20, were found dead hours after police say someone attacked them in their sleep on Nov. 13.
The three women lived there and Chapin was visiting his girlfriend, Kernodle. Authorities have said they found no signs of forced entry.
Two of the victims were sleeping on the second floor, and two were on the third.
All four attended the University of Idaho.
Chapin was a member of the Sigma Chi fraternity, the University of Idaho said earlier this month. Kernodle and Mogen were both part of the Pi Beta Phi sorority, and Goncalves belonged to Alpha Phi.
"We worked through the holiday," Snell told Fox News Digital in an interview at the Moscow police headquarters Friday. "This is a nonstop investigation and will continue to move forward."
At the same time, investigators were revisiting the home.
They were seen searching an upstairs bedroom and looking just inside the front door on the bottom floor. Two roommates on the ground level and a pet dog were unharmed in the attack.
After searching the inside of the house, one of the investigators left with several small paper bags in his hand.
"Detectives continue investigating and will collect evidence," Snell told Fox News Digital. However, he added that he did not have details about what authorities removed specifically from the scene Friday afternoon.
Fox News contributor and former Washington, D.C., homicide detective Ted Williams said he thinks police returned to the scene after determining the killer came and went through the sliding glass door at the rear of the home.
"Remember the two surviving witnesses slept on the first floor, so it is highly unlikely that the killer(s) came or went through the front door," he said.
Snell said investigators were taking all possibilities seriously in order to avoid tunnel vision.
"The people that are working this case from all three agencies, they're the best and the brightest, and they have the most up-to-date resources," he said.
Investigators were looking into all possibilities 12 days after the attack, according to authorities, who spent Thanksgiving Day analyzing evidence and conducting interviews.
Most students have left town for the Thanksgiving holiday, but University of Idaho President Scott Green has said that all students will have the option to finish the semester remotely.
Snell said if the suspect turns out to be a student who doesn't plan on returning, that won't hinder investigators.
"We're going to continue this investigation no matter what," he said. "That's going to be putting together the various pieces and ultimately coming up with the suspect or suspects and then making that arrest."
Police have not yet identified a suspect or recovered the murder weapon – believed to be a fixed-blade knife. All four victims had been stabbed to death, and some had defensive wounds, according to authorities.
"Whether or not that person is here on campus, or in their room, online, or wherever in the community, we're going to make that arrest," Snell said.
Police say they've already ruled out the two female roommates who were downstairs at the time of the murders, a man who appeared on surveillance video at a food truck at the same time as Goncalves and Mogen shortly before they returned from a night out, a "private party" driver who took them home, Goncalves' ex-boyfriend and a group of friends who were present at the house Sunday morning when the initial 911 call was placed.
Police say they believe the attack was targeted and are asking the public for information and surveillance video.
They are also looking into a claim that Goncalves may have had a stalker.
Anyone with information on that topic is also asked to reach out to police — no matter how small the details may be.
"We continue looking into the stalker issue and are asking for any information from the public on this topic," Snell said.