MOSCOW, Idaho - Six weeks before four University of Idaho students were brutally murdered in their off-campus home, police officers were called to the residence over a loud party, but none of the eventual victims were present.
Officers arrived at the home at about 8:45 p.m. on Sept. 1 and knocked on the front door for a few minutes before two unidentified males came downstairs to talk to them.
"I just looked for everyone that lives here, and they're not here right now," one of the males said. "I have no clue where they went. No clue."
After one of the officers noted that there may be underage drinking and said he just wants to deal with it as a noise complaint, one of the males offered to try to get someone who lives there on the phone.
Officers eventually spoke with 21-year-old Maddie Mogen, a resident of the home and one of the four victims who would eventually be murdered.
"The reason that we're here is that we received a noise complaint of loud music and partying," the officer told Mogen over the phone.
"None of the occupants who live at this address are here right now. So now you have a house full of random people. You need to let them know that the noise needs to come down."
Mogen was apologetic and told the officers that she was frustrated but would make sure the music is turned down.
"I'm so sorry, once again," Mogen said.
"If I were you guys, I'd probably just come home and make sure that whoever is partying here is keeping it down to a minimum," the officer told her.
The noise complaint was called in about six weeks before Mogen was murdered, along with Kaylee Goncalves, 21, Xana Kernodle, 20, and Ethan Chapin, 20.
Ted Williams, a former Washington, D.C., homicide detective, said he believes the killer had likely been in the home before and knew the layout well, potentially complicating the investigation given the number of people who were constantly in and out of the house.
There is also likely a massive amount of physical evidence that investigators have had to sift through, according to Williams.
"This very well may be why it is so difficult for law enforcement to process the crime scene, because this location where these four victims were killed, was considered a party house," Williams told Fox News Digital.
"Quite naturally, there would be a great deal of DNA and other physical evidence at that scene, and so what law enforcement is trying to do right now is to go through a process of elimination."
Police still have not identified a suspect, but say that a fixed-blade knife was used to stab all four victims multiples times between 3 a.m. and 4 a.m. on Nov. 13.
A neighbor previously described the residence as a "party house" where large groups could be seen any night of the week.
"There were parties that were kind of loud," the neighbor told Fox News. "As I would take my dog in and out to go to the bathroom, I would just be walking by, I would look up, and I would see people in the windows almost every night, probably four or five nights a week. There were a lot of people that went into and out of that house pretty frequently."
More than 10,000 tips have poured in from the public, most recently leading police to search for a white 2011-2013 Hyundai Elantra that was spotted near the crime scene on the night of the murders.
Fox News' Jasmine Baehr and Ashley Soriano contributed to this report.