Detectives investigating the brutal murders of four college students nine days ago in Moscow, Idaho, have "looked extensively" into tips that one of the victims had a stalker, but have not been able to verify the information, police said on Tuesday evening. 

The Moscow Police Department said they've received "hundreds of pieces of information" related to Kaylee Goncalves potentially being stalked. 

A split photo of the deceased students.

University of Idaho students Ethan Chapin, 20; Xana Kernodle, 20; Madison Mogen, 21; and Kaylee Goncalves, 21.  (Jazzmin Kernodle via AP/Instagram/ @kayleegoncalves)

Goncalves was at a local bar with her roommate, Madison Mogen, before returning to their three-story home shortly before 2:00 a.m. The other two victims, Ethan Chapin and Xana Kernodle, were at a party at the Sigma Chi house before also returning home around 2:00 a.m. 

UNIVERSITY OF IDAHO STUDENTS KILLED: A TIMELINE OF EVENTS

Jim Clemente, a retired FBI supervisory special agent and criminal behavioral analysis expert, told Fox News Digital on Tuesday that the killer likely knew the victims or was a stalker familiar with their habits. 

"Going into an occupied dwelling with six people in … different rooms in the middle of the night is an extremely high-risk crime, unless he knows one or more of the people," Clemente told Fox News Digital. "So, that is my first thought on it: this offender did not just randomly choose this location, that he targeted one or more of the people in there. Now, that could be because he has a relationship or a past relationship with one or more of them, or it could be that he's been stalking one or more of them."

Ka-Bar knife inset in front of house where students were murdered.

Police suspect a KaBar knife may have been used in slayings of four University Idaho students, inset. Caution tape surrounds the house near campus where the students were slaughtered. (Credit: Ka-Bar / Derek Shook for Fox News Digital)

Police also confirmed Tuesday that the weapon used in the attacks was a "fixed-blade knife." A medical examiner determined during an autopsy last week that all four victims were stabbed multiple times and some had defensive wounds. 

IDAHO MURDERS: WHAT WE DON'T KNOW ABOUT BRUTAL SLAYINGS OF 4 UNIVERSITY STUDENTS

Detectives have been inquiring at local businesses about whether anyone has recently purchased a fix-blade knife

A local store owner told the Idaho Statesman that police asked him days after the attack whether he carries "Ka-Bar-style knives," a type of combat knife first issued to the U.S. Marine Corps in the 1940s that is "similar to the knife Rambo has." 

Blood seeping from the second-floor bedroom

General views of the house on November 16, 2002, where four students of the University of Idaho were murdered show red stains running down the foundation of the house in Moscow, Idaho. (Derek Shook for Fox News Digital)

Home with police tape and four vehicles in front

Police search a home in Moscow, Idaho on Monday, November 14 where four University of Idaho students were killed over the weekend in an apparent quadruple homicide. The victims are Ethan Chapin, 20, of Conway, Washington; Madison Mogen, 21, of Coeur d'Alene, Idaho; Xana Kernodle, 20, of Avondale, Idaho; and Kaylee GonCalves, 21, of Rathdrum, Idaho. (Derek Shook for Fox News Digital)

More than 100 law enforcement officers from the FBI, Idaho State Police, and Moscow Police Department are investigating the case. 

One officer could be seen carrying evidence boxes out of the home on Tuesday, while other officers expanded the crime scene to include a parking lot and forested area in the rear of the home on Monday. 

Police search in Moscow, Idaho for clues in the murders of four college students

Investigators are seen searching parking lot area behind the house in Moscow, Idaho Monday, November 21, 2022, where four people were slain on November 13. (Derek Shook for Fox News Digital)

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Police will hold a news conference on Wednesday to update the public about their investigation. 

Fox News' Stephanie Pagones contributed to this report.