Investigators scouring the Moscow, Idaho, crime scene for signs of a suspect could find answers from the nearby cell phone towers, which — when used appropriately — can provide clues as to who was in the area and when.
Wednesday was day 10 of the search for a suspect behind the horrific murders of four University of Idaho students who were believed to have been stabbed in their sleep after a night out. While investigators have been seen poring over the King Road crime scene, they might also find answers by examining data from the nearby cell towers, mobile forensics expert Tom Slovenski told Fox News Digital.
"When you do a digital investigation, the towers are the power," Slovenski said, when reached by phone. "The towers can tell you so much that the phone cannot."
Slovenski, founder and president of Cellular Forensics, LLC, said investigators would likely seek warrants for any of the digital devices recovered at the scene or from the victims, but also the cell tower call detail records, or CDRs. CDRs provide details of "transactions" — any activity a person performs on a digital device — for any cell phones in the area, each of which is differentiated by a specific identification number.
"It will show on these call detail records the time of the transaction, the date of the transaction, the tower that was utilized in the transaction," Slovenski said. "The side of the tower that was utilized in the transaction. The longitude and latitude of that tower, that specific tower that was used, along sometimes with the actual street address."
Even when someone is not using their cellphone, the device is still registering a location. But such detailed data can only be pulled from the towers, not from the device itself, Slovenski said.
He noted that warrants or subpoenas are required to obtain such data, and a judge must consider the importance of "finding the killer" versus the public’s privacy.
"You’re going to have to convince the judge that it’s worth it," he went on.
With the necessary permission, an investigator could even determine through a cell tower analysis which cellphones were in a certain area at a certain time, he explained.
"You can do what’s called a tower dump," Slovenski said, "but you really gotta know what you’re looking for."
Tower dumps, he said, are more often successful in rural areas, where one tower encompasses more space, than urban areas, where three towers could cover a smaller region.
"The thing is, you’ve gotta be very specific with tower dumps, and they take a lot of time to go through," he said. "And again, all of this stuff now, all of this information, you’ve gotta have a warrant or a subpoena — the cell tower companies will not give you this."
He called analyzing a tower dump "a lengthy process," and one that required investigators be as specific as possible in terms of the parameters for the data they are requesting.
And even when investigators do receive the trove of data from a tower dump, they must still weigh the information they’ve gathered to determine if it’s pertinent.
"Just because you’ve got a tower near you does not mean that that tower was utilized by you," he said. "A cellphone responds to the best signal, not the closest tower. You could be looking down the street and see a tower — that doesn’t mean you’re on it."
He added: "It depends on a lot of factors in the area as to what towers your calls are going through."
When utilizing tower dumps or other data, such as that which can be pulled from Google, investigators must also question whether a person’s presence in an area is relevant to their investigation, Slovenski said.
"You could have been passing by on the street and your number got caught up in it," he continued. "You know, while someone's inside getting killed, here comes the trash truck and the trash truck driver's got a phone… You have to go through and use common sense, and you’ve got to say: ‘Okay, how many times was this device in this quadrant? And did it stay for any length of time?’"
Moscow police received a call shortly before noon on Nov. 13 for a report of an "unconscious person" at the King Road home. Several other people had gathered at the address by the time police arrived, officials said.
The victims were identified as Ethan Chapin, 20, of Conway, Washington; Madison Mogen, 21, of Coeur d'Alene, Idaho; Xana Kernodle, 20, of Avondale, Arizona; and Kaylee Goncalves, 21, of Rathdrum, Idaho.
They were believed to have been killed on the second and third floors of their home between 3 a.m. and 4 a.m. on Nov. 13 after they spent the night out.
Two other roommates were inside the home, on the bottom floor, at the time of the murders but were uninjured.
The victims are all believed to have been asleep when they were attacked, though some showed signs of defensive wounds. Each victim was stabbed several times and showed no signs that they were sexually assaulted. They are all believed to have been killed using a single knife.
Officials said late Tuesday that investigators had received information that Goncalves could have had a stalker. Investigators "looked extensively" into those reports, and "have pursued hundreds of pieces of information" related to the stalker tip. As of Tuesday, they had been unable to confirm the information or identify a stalker.
Moscow Police Department officials are asking the public to share all outside surveillance video taken from 3 a.m. to 6 a.m. on Nov. 13 from businesses and residences within a specific area.
A manhunt continues for the person or persons involved in the attack. Police are asking anyone with information or footage related to the slayings to contact 208-883-7180 or firstname.lastname@example.org.
Fox News Digital's Ashley Papa contributed to this report.