Who savagely killed these four friends as they slept in their shared student house? 

One morning, nearly a month ago, Kaylee Goncalves posted on her Instagram account some endearing pictures of herself with four of her housemates: all students living in the quaint college town of Moscow in northern Idaho.

Their faces are wreathed in smiles. In one photo, Kaylee has her friend Madison Mogen on her shoulders — and another housemate, Xana Kernodle, is cuddling up to her boyfriend, Ethan Chapin.

‘One lucky girl to be surrounded by these ppl every day,’ wrote Kaylee in the caption.

Yet by the following morning — November 13 — those four students would be dead, fatally stabbed in their house in a gruesome quadruple murder that has stunned the U.S.

Kaylee Goncalves posted on her Instagram account some endearing pictures of herself with four of her housemates (Pictured: Kaylee second from left)

Of the five flatmates in the house, the two sleeping in ground-floor bedrooms apparently slept through the murders of the others upstairs

Of the five flatmates in the house, the two sleeping in ground-floor bedrooms apparently slept through the murders of the others upstairs

According to the coroner, Cathy Mabbutt, there was ‘quite a bit of blood’, the victims’ wounds were ‘pretty extensive’ and the three-storey house in which they were slain was in a chaotic state.

She added: ‘I’ve been a coroner for 16 years . . . we have had multiple murders in the past, but nothing, nothing like this.’

Ethan, 20, Madison, 21, Xana, 20, and Kaylee, 21, were all students at the University of Idaho. They were brutally attacked between 3am and 4am — and four weeks on, the killer has yet to be caught.

Ethan had been staying with girlfriend Xana that night. Of the five flatmates in the house, the two sleeping in ground-floor bedrooms apparently slept through the murders of the others upstairs.

It’s hard to think of a recent case that has so gripped America. The fascination is in large part down to the fact that so many people can relate to the victims: four middle-class young people making their way through state university.

Beyond the fact that the housemates had a reputation for throwing noisy parties — neighbours said there were often students coming and going — there has yet to be any hint of drugs or any other criminal activity behind the murders.

Madison Mogen had been studying marketing and hoping to travel around the world when she graduated next year.

Kaylee Goncalves, her best friend since school, planned to move to Texas, having been promised a job in a marketing firm in Austin.

Ethan Chapin, one of triplets, played basketball and had a big smile. He and his girlfriend, Xana Kernodle, had diligently worked their way through college by working shifts as waiters at a local Greek restaurant.

The coroner believes all four were probably asleep in bed — two of the girls reportedly sharing the same one — when they were each stabbed multiple times with a large knife.

None showed any signs of sexual assault and some had injuries that suggested they’d tried to fight back.

Police were alerted at noon the following day after the two housemates downstairs woke up and raised the alarm.

Madison Mogen (pictured: left), 21, had been studying marketing and hoping to travel around the world when she graduated next year

 Madison Mogen (pictured: left), 21, had been studying marketing and hoping to travel around the world when she graduated next year

Police found no sign of forced entry or damage at the rented house, which had a front door with a coded entry system that visitors said was rarely activated, as well as a sliding glass door into the large kitchen and living room around the back of the building.

Four weeks on, shock has turned to anger and fear in the town of 25,000 people as police have failed to identify a suspect or a motive.

Initially, police said there was no threat to the wider community. They then retracted that statement three days later, and now say they believe it was a ‘targeted attack’ — but won’t say whether the target was the house or its occupants.

Moscow’s mayor Art Bettge further muddied the waters, initially calling it a ‘crime of passion’ and later admitting that was only a possibility.

Steve Goncalves, the father of murdered Kaylee, is so despondent about the official investigation that he has hired a private detective to take up the hunt for the killer.

This week, Moscow police chief James Fry — himself an alumnus of the university — wept in a TV interview as he insisted: ‘This case is not going cold . . . I’m a dad with daughters and it’s tough — we’re human.’

Many of the university’s 9,000 students refused to return to the campus after the recent Thanksgiving holiday, while those who have remained are locking themselves in their rooms, reinforcing their windows or sharing rooms for comfort and protection.

Many are walking around only in groups and are avoiding venturing out after dark. At least one father has admitted he’s given his undergraduate daughter a gun.

The overwhelmed small local police force — which has been reinforced by some 80 FBI agents and state police — say they’ve been inundated with panic calls from local residents, particularly students, taking fright at anything from a man walking around to a car being revved up in a car park.

The investigators have also been swamped by more than 5,000 tips. They’ve conducted 150 interviews, collected 113 pieces of evidence and taken 4,000 crime-scene photos.

Earlier this week, investigators decided to return the victims’ possessions — including a pair of pink cowboy boots that had sat poignantly in Madison Mogen’s window — back to their families.

And yet there have been very few leads.

On Wednesday this week, police finally announced that they wanted to talk to the occupants of a white Hyundai Elantra seen in the area at the time of the killings.

And on Thursday, a neighbour reported having seen the house’s front door wide open at 8.30am on the morning of the murders. 

Earlier this week, investigators decided to return the victims¿ possessions ¿ including a pair of pink cowboy boots that had sat poignantly in Madison Mogen¿s window ¿ back to their families

Earlier this week, investigators decided to return the victims’ possessions — including a pair of pink cowboy boots that had sat poignantly in Madison Mogen’s window — back to their families

Otherwise, the investigation has been eerily quiet and the killer — or killers — remain at large.

However, police have at least been able to piece together a chain of events in the hours leading up to the killings.

It had been a particularly energetic Saturday night of socialising as the university’s American football team had just played its last game of the season.

Xana Kernodle and Ethan Chapin, who had been in a relationship since the spring, went to a party at the university’s all-male Sigma Chi fraternity house a short walk away from their own building at about 9pm. 

They returned to Xana’s house on King Road at 1.45am.

The same evening, the two other murdered housemates — Madison Mogen and Kaylee Goncalves — had been drinking at a local bar together and stayed there until 1.30am.

About ten minutes later, a video camera captured them stopping at a late-night food van. 

They chatted with friends for a little while until someone — described by police as a private individual — gave them a lift home.

At 1.56am, they were shown returning to their house on King Road in a neighbour’s surveillance camera footage.

Then Kaylee apparently started making a lot of phone calls. Between 2.26am and 2.52am, seven unanswered phone calls were made from her phone to a friend, according to her family. Police say several calls to the same friend were also made from Ms Mogen’s phone.

According to Kaylee’s sister, Alivea, the calls were made to a student named Jack DuCoeur, who had been Kaylee’s boyfriend for several years until they had recently — and amicably — broken up.

Jack has yet to discuss the contents of those calls, although Alivea said she and her family stand behind him ‘100 per cent’ and ‘know he absolutely had nothing to do with this at all’.

She has cautioned that it would be dangerous to make too much of the calls as her sister often did this, ringing friends incessantly, sometimes in the early hours, just to ask their advice on what she should have for a meal.

The two surviving housemates, Bethany Funke and Dylan Mortensen, were both separately out of town that night and had returned by 1am — before the others got back.

Police say they have ruled the pair out as suspects, as they have Jack DuCoeur, a man seen with Ms Goncalves and Ms Mogen at the food van, the individual who gave them a lift home and the dead students themselves.

Friends described Kaylee Goncalves and Madison Mogen, blondes who looked and dressed alike, as an ‘inseparable duo’ who had an ‘unstoppable, loving relationship’ and regarded themselves as sisters.

Kaylee’s father, Steve, said the pair had been close friends since they were 12.

‘They went to high school together,’ he said in a speech at a memorial vigil at the university. ‘Then they started looking at colleges. 

They came here together. They eventually get into the same apartment together. And in the end, they died together, in the same room, in the same bed.’

But are other students now at risk of meeting the same gruesome fate?

No one knows, but the lack of information through official channels has inevitably opened the floodgates to endless speculation, rumours and theories from the tens of thousands of people avidly following the case online. 

Dozens of Facebook and Reddit groups and threads — some with 80,000 members — have been speculating on the case, with some people even watching a livestream of a community vigil for the victims and sharing screenshots of anyone they thought ‘looked suspicious’.

Many of the university¿s 9,000 students refused to return to the campus after the recent Thanksgiving holiday

Many of the university’s 9,000 students refused to return to the campus after the recent Thanksgiving holiday

Steve Goncalves, who has spoken to investigators, has been telling the media his own theories about what happened.

He believes his daughter may have been the main target as her injuries were more brutal than those to her best friend Madison Mogen lying beside her in bed.

Kaylee had also reportedly complained about being followed by a ‘stalker’ — although police say they haven’t been able to corroborate this.

Mr Goncalves has also said the killer entered the house through the sliding glass doors at the back of the building — and many of the amateur detectives scrutinising the evidence online agree with him.

Using aerial shots, they’ve posited a chilling scenario whereby the killer could have stood unobserved in a nearby line of trees and looked straight into the house’s well-lit large main room through the floor-to-ceiling glass sliding doors. 

They may not have been locked as it was, after all, a student house.

Professor Joseph Scott Morgan, a forensics expert at Jacksonville State University, told the Mail that the presence of FBI behavioural profilers in the investigation indicates that the team is looking for similarities with other cases.

That could mean a serial killer, and experts have already pointed out two that have previously targeted female students in their lodgings.

One was the notorious Ted Bundy, who broke into an all-women student sorority house in Florida in 1978 and bludgeoned to death two of its occupants, nearly killing two others.

Prof Morgan said that ‘quite striking’ parallels were made with the 1990 ‘Gainesville Ripper’ case which inspired the Hollywood blockbuster film Scream.

The use of edged weapons, the targeting of student accommodation on the edge of campus and the killing of several people in the same building was ‘something you don’t normally see’, Prof Morgan added.

It may only be a bizarre coincidence but the university’s film department had put on a screening of Scream at a Moscow cinema just a month before the murders.

Former FBI profiler Mary Ellen O’Toole said the killer had to be someone ‘comfortable’ with using a large knife and, given how many people were in the house in a built-up area, ‘experienced going into strangers’ homes’.

Or perhaps someone who knew the interior of this one pretty well. Given it was a notorious ‘party house’, many people would have known it, including perhaps who slept in which rooms.

The housemates also recently posted a TikTok video of themselves wandering around their home imitating each other.

‘It sent a chill up my spine when I saw it,’ said Prof Morgan, as it revealed who lived in the house and its layout to anyone who might have wanted to know.

Clearly, a lot of people have visited the building and need to be ruled out of the investigation, and former FBI investigators have warned that it could take a long time to find the killer.

But Americans are impatient for results and the fearful citizens of Moscow, Idaho, are desperate to know they can sleep safe at night.

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Read more at DailyMail.co.uk