The five young women at 1122 King Road in Moscow, Idaho, were living the kind of lives Americans kids can't wait to begin.
WARNING: Some readers might find the details in this story distressing
Halfway through their studies at the University of Idaho, the students had decided to move off campus and into a share house.
The sprawling three-storey home on a quiet cul-de-sac was a 15-minute walk from campus, with enough space for everyone to enjoy their privacy.
But police insist the house wasn't so big that no-one would have heard if they screamed in the early hours of November 13.
At some point, as Madison Mogen, Kaylee Goncalves, Xana Kernodle and her visiting boyfriend Ethan Chapin slept, someone crept into the house.
All four were stabbed in their beds with what police say was an "edged" weapon, perhaps a "fixed-blade knife".
Meanwhile, two more housemates were fast asleep on the first floor and didn't hear a thing.
They didn't realise a massacre had occurred in their own home until the next day when they went to rouse their friends.
The ABC is choosing not to name the survivors to protect the young women's privacy.
With no murder weapon, no suspect, no motive, and hundreds of tips to sift through, police are racing to solve what appears to be a senseless slaughter of young people who thought they had their whole lives ahead of them.
Despite initially reassuring this small college town of 26,000 that there was nothing to worry about, authorities now admit that with no suspects or leads, police "cannot say that there is no threat to the community."
Amid a frenzy of speculation, police are saying little about reports that one of the victims may have had a stalker.
They are also declining to comment on apparent parallels with a stabbing murder 600 kilometres away that also remains unsolved.
An ordinary Saturday night turns deadly
In the hours leading up to the quadruple homicide, all of the housemates were out on the town enjoying themselves on a typical Saturday night in Moscow, Idaho.
Madison Mogen and Kaylee Goncalves, both 21, were longtime best friends and went to a local bar together to grab a drink.
Afterwards, they ordered some pasta at a food truck where witnesses insist nothing appeared to be amiss. They then headed back to the house.
Ethan Chapin and Xana Kernodle, both 20, spent the evening at a frat party before getting home at about 1:45am.
The surviving housemates had returned home a little earlier — about 1am — and were likely already asleep when the others arrived.
At 2:44am, Kaylee made six phone calls to her ex-boyfriend who is only being referred to by authorities as 'Jack'.
All of her calls went unanswered.
Madison made three calls to the same man several minutes later, but again he did not pick up.
Kaylee made a seventh and final call, but Jack, who was also a student at the University of Idaho, was asleep.
Police say they have no idea why the two women were trying to reach him, but they say the man had nothing to do with what unfolded next.
Autopsies suggest most of the victims were asleep when their killer struck.
But Kaylee's father Jeffrey Kernodle said it's clear from the post-mortem that his daughter was awake and trying to fight for her life.
"She's a tough kid. Whatever she wanted to do, she could do it," Mr Kernodle told his local news station KTVK/KPHO.
The families of the victims cannot understand how anyone managed to break into the house, which had an automatic lock that required a code to open.
"It doesn't make sense," he said.
Kaylee's sister Alivia insists all the housemates were conscious of their safety, and kept their shared home secure.
"They were smart, they were vigilant, they were careful and this all still happened," she said in a statement.
"No one is in custody and that means no one is safe. Yes, we are all heartbroken. Yes, we are all grasping.
"But more strong than any of these feelings is anger. We are angry. You should be angry."
A grisly discovery
By midday the next day, the housemates on the first floor decided their friends had been sleeping long enough and went upstairs to check on them.
There, they made a frantic call to emergency services, asking for an ambulance to come check on a friend who appeared to have fallen down and passed out.
Authorities say the surviving housemates have been eliminated as suspects, but have no clue why their lives were spared.
Was the killer looking for the four sleeping students on the second floor? Did they simply not realise that there were also bedrooms on the first floor?
Kaylee's pet Australian Shepherd, Murphy, was in the house during the murders, but was also unharmed.
No valuables were stolen and no property was damaged.
Detectives said they believe the murders were an "isolated, targeted" attack, but declined to elaborate.
"To be honest, you're going to have to trust us on that at this point, because we are not going to release why we think that," Moscow Police Captain Roger Lanier said.
But after initially downplaying the risk to others in the town of Moscow, authorities are now urging locals to be vigilant.
"We do not have a suspect at this time," Moscow Police Chief James Fry said.
Whoever committed the crime, he warned, "is still out there."
The 'stalker' and the eerily similar stabbing
In the two weeks since the murders, Idaho authorities have marshalled dozens of police to process 1,000 tips from the public.
They have interviewed 150 potential witnesses, collected more than 100 pieces of evidence from the house and taken 4,000 photographs.
Local hunting shops say they've received multiple visits from detectives asking them to check their records for knives sold in recent weeks.
National media outlets have descended on the small Idaho community and TikTok sleuths are dissecting police press conferences and pouring over the victims' social media accounts for clues.
Moscow police have confirmed that they received "hundreds" of tips that prior to her death, Kaylee told friends she may have had a stalker.
"We obtained information through some of our interviews that Kaylee had made some comments about a stalker. So that's where that came from," Captain Roger Lanier told reporters.
"We have followed up looking at specific time frames and specific areas of town. So far, we have not been able to corroborate it, but we're not done looking into that piece of information."
Police are also investigating any potential links between the Idaho massacre and a frenzied stabbing attack on a sleeping couple in the neighbouring state of Oregon.
In the early hours of August 13, 2021, Travis and Jamilyn Juetten woke to find a knife-wielding assailant in their bedroom.
Jamilyn survived 19 stab wounds. Her husband Travis fought off the attacker, but was pronounced dead at the scene.
More than a year later, the killer remains at large.
"We're looking at every avenue and we have other agencies reaching out to us with other cases, stuff that we are going to follow up on," Chief Frye confirmed.
As police chase leads, those who knew and loved the young housemates wait for answers that may never come.
"They were daughters, sisters, aunts, best friends and humans," Alivea Goncalves said.
"No amount of words or statements could ever attempt to capture who they were or what they wanted in life or what was stolen from us all."
