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.
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.
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."
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.
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."
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 will hold a news conference on Wednesday to update the public about their investigation.
Fox News' Stephanie Pagones contributed to this report.