Some of the University of Idaho students were "stabbed in their beds" at a rental house last Sunday, a coroner has revealed.
Cathy Mabbutt, Latah County coroner, confirmed the four students were killed with a "large knife" after autopsy reports concluded the victims were stabbed to death in Moscow, Idaho, US.
The victims were stabbed in the chest and upper body, as Moscow Police Department confirmed there were no signs of sexual assault.
According to police, the students were likely asleep when the attack happened, and some of the victims had defensive wounds as they tried to fend off the attack.
Ms Mabbutt believes the suspect would have had to be very angry to stab four people, she told NewsNation: “It has to be somebody pretty angry in order to stab four people to death.”
Police have still not identified a suspect or found a weapon, according to Moscow Police Chief James Fry.
Madison Mogen, 21, Kaylee Goncalves, 21, Xana Kernodle, 20 and Ethan Chapin were tragically found dead on Sunday afternoon.
The victims were all close friends with Ethan Chapin and Xana Kernodle both in a relationship together.
Investigators said evidence found at the house has led them to believe the pupils were targeted - but have refused to give any more details.
Police said nothing was taken from the victims or the home.
The cops drew criticism from the local community after they claimed there was no ongoing danger to the wider community - despite four students being stabbed to death.
Authorities have since changed their stance, as police believe there now could be a threat to the local area.
Mr Fry said: "We cannot say that there is no threat to the community. We still believe it's a targeted attack. But the reality is there still is a person out there who committed four very horrible, horrible crimes."
There were two other people found unharmed in the house as police refuse to discuss whether they saw the killings or could provide an account of who called 911.
According to police, there was no sign of forced entry at the home as cops arrived to the front door being open.
There are investigations into if the "large knife" was recently purchased in the area as police ask local businesses for possible information and vital clues.
Three rubbish dumpsters near the residence had been seized by detectives as they investigated the area for potential evidence.
The Idaho State Police, the FBI and the Latah County Sheriff's Office are investigating the incident.
