Police say 22-year-old McKay Hutton shot three family members, including his mother and a two-month-old baby, and then took his own life in a Fairbanks hotel room on Friday.
The Fairbanks Police Department on Saturday identified the murder-suicide victims as McKay Hutton; Linda Hutton, 54; Emily McDonald, 22; and eight-week-old Teagan Hutton.
"Motivation is still under investigation," police said in a written statement.
McKay Hutton has been identified as the son of Linda Hutton, said police spokesperson Yumi McCulloch. Police are still confirming the relationships between the victims, she said.
"They're a family, all related," said officer Doug Welborn.
McKay Hutton's and McDonald's Facebook pages list them as married to one another. McDonald put her name on Facebook as Emily McDonald-Hutton.
Hutton's page shows him holding an infant in a photo posted in October, and the couple spending time together in pictures dating back to September 2015.
McKay Hutton listed a North Pole address when he registered to vote in March of this year, according to state records.
McCulloch said the victims were from the Fairbanks area. Police are continuing to look into what brought them to the hotel.
Officers responded to a call of a "suspicious circumstance" from staff at the Hampton Inn and Suites at 1:25 p.m. Friday, police said. A man sitting in the hotel's second-floor hallway directed officers to a nearby room where they found the four bodies, police said in a statement.
The man in the hallway was a family member whose name is not being released at this time, police said. A preliminary investigation determined he was not present during the shooting, they said.
The shooting is believed to have occurred shortly before police arrived. Someone staying at the hotel told police they heard a single gunshot in that time frame, Welborn said.
Officers found a semiautomatic firearm in the room, Welborn said. It was the only weapon recovered, he said.
There is no indication drugs or alcohol were involved, police said. The bodies will be flown to the State Medical Examiner's Office in Anchorage for autopsies.
Police urge anyone who had contact with the victims in the past few days to call detective Avery Thompson at 907-450-6549 or by email at firstname.lastname@example.org.