Four University of Idaho students were slain in their beds while they slept: What we know

• Authorities looking for more leads in fatal stabbing of Idaho college students.
• Two other roommates unharmed could be 'key' to investigation, authorities say.
• Victim's father said his daughter likely fought with killer during stabbing: 'She's a tough kid.'

The murder investigation into four University of Idaho students believed to have been stabbed to death while sleeping in their beds has left residents rattled and authorities trying to unravel a mystery that's garnered attention across the U.S. 

Sunday's crime has reverberated through the college town of Moscow, a city of about 26,000 people near the Idaho-Washington State border. Moscow hasn't had a murder in about five years. 

The victims were stabbed to death in their beds and likely were asleep, Latah County Coroner Cathy Mabbutt told NewsNation. Mabbutt would later tell CNN that she saw "lots of blood on the wall" when she arrived at the scene.

"It has to be somebody pretty angry in order to stab four people to death," Mabbutt told the cable news channel. The victims were stabbed in the chest and upper body, she said.

The coroner added that stab wounds on the hands of at least one victim appear to be defensive wounds and that there were no signs of sexual assault.

"We're looking for additional tips and leads," said Aaron Snell, a spokesman for the Idaho State Police told CNN on Friday.  "We believe that releasing information about the locations of the victims throughout the night might generate some information that we can follow up on."

Snell contends that the incident was "targeted" but would not say why as now state and federal authorities are on the hunt for who killed the students.

Here's what we know so far:

Who are the victims?

The four students have been identified as Ethan Chapin, 20; Madison Mogen, 21; Xana Kernodle, 20; and Kaylee Goncalves, 21. Each was either in a fraternity or a sorority and Kernodle and Goncalves were roommates.

Jeffrey Kernodle, the distraught father of Xana Kernodle, told Phoenix TV station KTVK/KPHO that he spoke to his daughter by phone before she was killed.

"I think midnight was the last time we heard from her, and she was fine," Jeffrey Kernodle told the station. The victim's father said that he doesn’t understand why his daughter and her roommates were killed.

"They were just hanging out at home. Xana was just hanging out at home with her boyfriend," Kernodle said. The father said his daughter and Chapin had a really strong bond.

Adding that the killings "doesn’t make sense," Kernodle told the station that the door of their daughter's off-campus residence opened with a number code.

“So, they either knew that, or they just kind of went around and found the slider [sliding door] open,” Kernodle said.

The father said the autopsy shows that his daughter likely fought with her killer, sharing a similar description made by the coroner. 

“Bruises, torn by the knife. She’s a tough kid," Kernodle said. "Whatever she wanted to do, she could do it."

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Police release new details

Authorities have not identified a suspect or found a blade that was used to stab the students, Moscow Police Chief James Fry said Wednesday. But the Idaho Statesman reported this week that police are searching for a military-style knife in connection with the killings.

That's similar to Mabbutt, the county coroner, telling NewsNation that the killer likely used a "pretty large knife."

Authorities on Friday released a map and timeline of the victims’ whereabouts last Saturday. The map shows the four students spent most of the night apart before meeting at home.

Chapin and Kernodle attended a party at Chapin's fraternity house from around 8 p.m. to 9 p.m. Goncalves and Mogen were at a sports bar between 10 p.m. and 1:30 a.m. They picked up food at a food truck at 1:40 a.m. before heading home.

While police initially said Goncalves and Mogen took an Uber home from the food truck, an updated statement Friday said the two "used a private party for a ride home from downtown."

Authorities say the four victims were back at the rental house by 1:45 a.m. Sunday, according to multiple reports. The bodies were found around noon Sunday.

Was anyone else home at the time?

Two other female roommates were found unharmed in the house, authorities said. Moscow Police Chief Fry declined to say Wednesday if they were able to provide an account of the killings or say who called 911.

When a reporter described the surviving roommates as witnesses, Fry clarified: "I don’t think I ever said they were witnesses. I said they were there."

Fry added there was no sign of forced entry at the home and a door was found open when officers first arrived at the scene. Nothing appears to have been stolen from the victims or the home, investigators said.

Snell, the Idaho Police spokesman, later told ABC News on Thursday that the two other people inside the house may be vital to the investigation. Snell said the roommates have been cooperative with investigators and can help with the timeline. 

"Potentially they are witnesses, potentially they are victims," Snell said. "Potentially they’re the key to this whole thing."

Fry, who initially said there was no threat to the community, had a different tone later in the week.

"We still believe it’s a targeted attack," Fry said. "But the reality is there still is a person out there who committed four very horrible, horrible crimes."

Contributing: Associated Press