A neighbor of four slain University of Idaho students whose shocking stabbing deaths remain unsolved nearly four weeks later claimed they saw the front door wide open hours after the slayings.

Kaylee Goncalves, 21; Madison Mogen, 21; Xana Kernodle, 20; and Ethan Chapin, 20, were found dead at a house just yards off campus, 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.

The neighbor told Fox News this week that the front door — which opens to the level where two other roommates were unharmed — was wide open around 8:30 a.m. on Nov. 13.

Police say they believe the stabbings happened between 3 a.m. and 4 a.m., when the victims were sleeping and as Moscow police officers were responding to an unrelated incident about a hundred yards away.

UNIVERSITY OF IDAHO STUDENTS KILLED: A TIMELINE OF EVENTS

First floor shower bathroom curtain

A shower curtain inside the home where the University of Idaho quadruple homicide occurred in Moscow, Idaho, is visible through an open door on Wednesday. A neighbor told Fox News that the same door was wide open the morning of the murders, hours after they took place and hours before police arrived. (Derek Shook for Fox News Digital)

A 911 call about a possible "unconscious person" was made from the phone of one of two surviving roommates around noon.

Authorities have kept mum about how they believe the killer entered and left the home.

When asked about the state of the front door when police arrived, a spokesperson told Fox News on Thursday "that type of information is part of the investigation and not released."

Chapin was a member of the Sigma Chi fraternity, majoring in recreation, sport and tourism management, the University of Idaho said. His frat house is across a field about 200 yards from the crime scene, and he and Kernodle were believed to have spent most of the evening there before returning to her place around 1:45 a.m., according to investigators.

University of Idaho victims

The four victims in the University of Idaho slayings on Nov. 13, 2022. (Instagram/@kayleegoncalves)

Kernodle and Mogen were both part of the Pi Beta Phi sorority and were marketing majors. Goncalves, a general studies major, belonged to Alpha Phi.

Two of the victims were sleeping on the second floor, and two were on the third, but police have not confirmed who was found where — or whether the bedroom doors were locked after the slayings. The survivors were both asleep downstairs, and a dog in the house was also unharmed.

The Latah County coroner later said that all four were victims of homicide by stabbing, and that their wounds had likely been inflicted in their sleep. "Some" of them showed signs they fought back, but police have declined to elaborate.

Dozens of investigators from the Moscow Police Department, Idaho State Police and the FBI have been working around the clock for weeks on the case.

"We are looking at all angles," Aaron Snell, the communications director for the state police, previously told Fox News Digital. "Our concept is that if we start getting pigeonholed into a specific idea, we may miss other tips in other pieces of this investigation."

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To that end, authorities revealed Wednesday they were seeking the occupant or occupants of a white 2011 to 2013 Hyundai Elantra seen near the victims' home around the time of the crime. Police are asking anyone who knows anything to come forward, even with minor details.

"Your information, whether you believe it is significant or not, might be the piece of the puzzle that helps investigators solve these murders," police said in a statement. 

Anyone with information is asked to call the tip line at 208-883-7180 or to email tipline@ci.moscow.id.us.

Canadian border authorities told Fox News Digital on Thursday that they are also on the lookout for the white Hyundai at the country’s ports of entry.

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Fox News’ Cristina Corbin contributed to this report.