Moscow, Idaho, police are looking for more information on the movements of University of Idaho students Xana Kernodle and Ethan Chapin, who were at the Sigma Chi fraternity house in the hours before they were killed along with two other Idaho students last month.
Police said the couple, both 20 years old, was believed to be at Chapin's frat house from 9 p.m. on Nov. 12 to 1:45 a.m. on Nov. 13.
Chapin and Kernodle's timeline "seems to be one of the larger areas that we don't have a lot of information in," Idaho State Police spokesman Aaron Snell told ABC News. "So, being able to locate what they did that night, and maybe who they contacted, maybe any routes that they took home, that would be important for the investigation."
Police are also looking for any details that could be relevant in the case overall, saying in a statement Monday: "We believe someone has information that will add context to the picture investigators are creating of what occurred. ... Your information, whether you believe it is significant or not, might be one of the puzzle pieces that help solve these murders."
Chapin, Kernodle and two of Kernodle's roommates, 21-year-old Kaylee Goncalves and 21-year-old Madison Mogen, were all stabbed to death in the girls' off-campus house on Nov. 13. Officials believe the attacks were between 3 a.m. and 4 a.m.
No suspects have been identified.
Two surviving roommates -- who police said are not suspects -- were home at the time and likely slept through the attacks, according to authorities. They were on the ground floor while the four students killed were on the second and third floors.
Police also addressed questions about the whereabouts of Goncalves' dog during the killings.
"We have not determined if the dog was inside the residence during the murders or not," Snell said. "What we do know is that the dog was inside when officers arrived. The dog did not appear to have any evidence on it."
"We don't believe that there was any appearance of forced entering into the home," Snell added.
Authorities also said Monday that they're still "looking into information about Kaylee having a stalker."
Police said they've spoken to two men who may have been the "stalker" Goncalves mentioned to friends and family. In October, the men were seen at a local business, and one of the men appeared to follow Goncalves into the store and then follow her as she headed to her car, according to police. The man never made contact with the college student, police said.
These men have since told police they were trying to meet women at the business, police said.
The authorities said there's no evidence these men were involved in the murders.
Police said "information about a potential stalker or unusual occurrences should go through the Tip Line."
Police urge anyone with information to upload digital media to fbi.gov/moscowidaho or contact the tip line at firstname.lastname@example.org or 208-883-7180.