MOSCOW, Idaho — Police have no suspects in custody a week after four University of Idaho students were murdered while sleeping in their off-campus home in Moscow, Idaho, on Nov. 13, authorities announced Sunday.

The community "must be prepared for a lengthy investigation," University of Idaho President Scott Green told reporters during the press conference.

While few questions have been answered after students Ethan Chapin, 20; Xana Kernodle, 20; Kaylee Goncalves, 21; and Madison Mogen, 21, were stabbed to death in their beds between 3 a.m. and 4 a.m. last Sunday, police have cleared several people as suspects in the case.

"We do not believe the following individuals are involved in this crime," Moscow Police Department Cpt. Roger Lanier told reporters on Sunday. "The two surviving roommates; a male seen at the Grubb Truck food vendor downtown, specifically wearing a white hoodie; [and] a private party who provided rides home to Kaylee and Madison in the early morning hour of November 13th."

UNIVERSITY OF IDAHO MURDERS TIMELINE: WHAT WE KNOW ABOUT THE SLAUGHTER OF FOUR STUDENTS

Moscow Police Department Cpt. Roger Lanier on Sunday listed several subjects whom police do not believe were involved in the quadruple homicide of four University of Idaho students on Nov. 13. (Derek Shook for WHD News Digital)

Lanider added that the "identity of the 911 caller and the 911 call have not been released," but police did clarify later that the 911 caller was not the perpetrator. 

Additionally, investigators are aware that Mogen and Goncalves made multiple phone calls to a male subject just before they were murdered but said they have reviewed and cleared those phone calls. 

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Authorities have not ruled out the possibilities of multiple potential suspects or suspects who may have been unknown to the victims.

Moscow Police Department Chief James Fry speaks at a press conference a week after four students were murdered near the University of Idaho campus.  (Derek Shook for WHD News Digital)

Idaho police stood by their Tuesday statement describing the murders as "an isolated, targeted attack."

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"We believe they were targeted because of the totality of circumstances we’re looking at," Moscow Police Chief James Fry said Sunday. "Not able to say if one person was being targeted."

The four victims were close friends and all part of Greek life on campus. 

University of Idaho students Ethan Chapin, 20; Xana Kernodle, 20; Madison Mogen, 21; and Kaylee Goncalves, 21.  (Jazzmin Kernodle via WHD/Instagram/ @kayleegoncalves)

Goncalves and Mogen spent Saturday evening downtown at a local watering hole called the Corner Club before they ordered food from the Grub Truck in Friendship Square. They were last seen in public on video footage captured by the food truck and shared publicly on Twitch, a live-streaming social media platform, before getting a ride home from a "private party" around 1:45 a.m.

UNIVERSITY OF IDAHO MURDERS: TWO ROOMMATES WERE AT HOME WHEN FOUR STUDENTS WERE KILLED

Kernodle and Chapin spent Saturday evening at a party at the university's Sigma Chi house before they returned home around the same time as Goncalves and Mogen. 

University of Idaho victims Maddie Mogen and Kaylee Goncalves seen in video footage hours before they were killed. (Twitch/ GrubTruckers)

The victims' two roommates had arrived home earlier, around 1 a.m. that Sunday.

IDAHO MURDERS: INSIDE THE OFF-CAMPUS HOUSE WHERE 4 STUDENTS WERE KILLED

Later that day, police responded to a 911 call made from one of the roommates' phones from the residence at 11:58 a.m. Fry told reporters on Sunday that a friend made the phone call but added later that it's unclear how many friends were at the scene of the crime before police arrived. It is also unclear how an estimated eight hours elapsed between the estimated time of the attacks and the time of the 911 call.

There were no signs of forced entry at the house, according to authorities.

Police search a home in Moscow, Idaho on Monday, November 14, 2022, where four University of Idaho students were killed over the weekend in an apparent quadruple homicide.  (Derek Shook for WHD News Digital)

On Thursday, the Latah County coroner announced that the four students all died of homicide by stabbing, likely while they were asleep. Police said Sunday that "some" of the victims had defensive wounds, and they all had multiple stab wounds.

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Fry said Sunday that police do not know how the murders occurred without the other two roommates hearing the attacks.

Authorities are asking anyone with information about the incident to call 208-883-7180 or tipline@ci.moscow.id.us.