A former FBI detective says the five cars towed from the Moscow, Idaho, house where four University of Idaho students were killed on Nov. 13 were likely an afterthought for investigators.

Ethan Chapin, 20, Xana Kernodle, 20, Madison Mogen, 21, and Kaylee Goncalves, 21 were stabbed to death early that Sunday between 3 and 4 a.m. in a Moscow, Idaho, home on King Road, near the college campus, according to police.

The attacker likely used a "fixed-blade knife," police said, adding that a suspect has yet to be identified.

Officials say the victims were likely sleeping when they were attacked, stating that each victim was stabbed multiple times.

IDAHO MURDERS: SLAIN STUDENTS' CARS TOWED FROM CRIME SCENE TWO WEEKS AFTER GRISLY ATTACK

Cars of four slain college students towed to impound

Cars possibly belonging to the four slain University of Idaho students are towed to impound for investigation by the police (Fox News Digital/Adam Sabes)

More than two weeks after the students were killed, police were seen assisting in towing the vehicles from the driveway at the house Tuesday.

Idaho State Police Communications Director Aaron Snell told Fox News Digital the vehicles were being transported to "secure long-term storage" for "further evidence gathering." The vehicles were taken to a nearby maintenance shop owned by the city.

During an interview Wednesday, Snell said that the cars were previously searched.

UNIVERSITY OF IDAHO HOLDS VIGIL HONORING FOUR SLAIN COLLEGE STUDENTS: 'WE LOST FOUR BEAUTIFUL SOULS'

"I believe that all of those vehicles had previously been searched, and they're still part of the crime scene," Snell said. "So as the possibility comes forward, there's additional evidence that we might be able to get and need that we will still have access to those vehicles."

Goncalves, Kernodle and Mogen lived at the off-campus house.

Ken Mains, a former FBI detective, told Fox News Digital the vehicles likely weren't towed until two weeks after the killings because there was likely little thought they had something to do with the crime.

Towed cars in Moscow, Idaho murders

A Range Rover believed to be Kaylee Goncalves' and several other cars of unknown ownership were towed from the scene of the quadruple homicide in Moscow, Idaho. (Derek Shook for Fox News Digital)

"I think, and I’m assuming here based on my experiences, they had a briefing and getting the vehicles was something discussed based on what I said above. It was an afterthought because they ‘most likely’ have nothing to do with the crime or hold no forensic or investigative value," he said. "Yet, someone was intelligent enough to say, ‘Hey, let’s take those vehicles, just in case.’ It’s smart and the correct decision. It doesn’t matter if it’s two weeks later because they were kept."

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

He added that investigators will go through every aspect of the vehicles for potential evidence.

"They will be looking for potential clues in those vehicles. Maybe a slip of paper with a number or name on it. Anything that would help point them in a direction," Mains said. "They are towing them to their impound lot, so they can do a more thorough search where they can take their time and meticulously go through any possible evidence."

Mains added that the vehicles are needed for any case that will be built in the future. 

IDAHO MURDERS: TWO WEEKS HAVE PASSED SINCE FOUR COLLEGE STUDENTS STABBED TO DEATH AT OFF-CAMPUS HOUSE

Idaho teens last photo

Ethan Chapin, 20, Xana Kernodle, 20, Madison Mogen, 21, and Kaylee Goncalves, 21, along with the women's two other roommates, in Kaylee Goncalves' final Instagram post, shared the day before the slayings. (@kayleegoncalves/Instagram)

"If you have released the vehicle to the family and then have to go back and reclaim it to process it for evidence, you are in a world of trouble, not only forensically. But if the case ever goes to trial, you handed the defense a big opening statement that police don’t know what they are doing," Mains said, adding that investigators should be able to obtain DNA samples even with the vehicles being outside two weeks.

A memorial for the slain students at the University of Idaho

A memorial for the slain students at the University of Idaho is covered in snow Monday, Nov. 28, 2022. The memorial is for the victims of a Nov. 13 quadruple homicide at an off-campus home. (Derek Shook for Fox News Digital)

Former FBI special agent Jonathan Gilliam told Fox News Digital investigators are going to want to look for fingerprints and DNA evidence inside the vehicles.

Gilliam said if the killer is someone the students knew, "there's a chance that they had been in that car." 

The former FBI special agent said he thinks investigators waited too long to tow the vehicles because the cold weather may have broken down potential fingerprint evidence.

"And so it makes sense that they have carried them away. I do think it's a little late in the game because it's so cold there, and the environment could have broken down some of that evidence, like fingerprints, for instance, and things like that," he said. 

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Anyone with information about the stabbings is being asked to call Moscow Police at 208-883-7054 or email tipline@ci.moscow.id.us.

Fox News' Michael Ruiz, Paul Best, Stephanie Pagones, and Audrey Conklin contributed to this report.