Police in Utah arrested a 32-year-old man on Saturday for the fatal shooting of three people, including a 2-year-old girl, who shared his northwest Salt Lake City home.

Alexander Hung Tran, 32, was arrested Saturday after officers found him the night before inside the home with a gun, Salt Lake City police Detective Richard Chipping said.

Police went to the home looking for relatives of an 8-year-old boy whose family failed to pick him up from school on Friday.

After Tran was found inside the home Friday evening, officers discovered the bodies of 50-year-old Heike Poike, her 2-month-old granddaughter Lyrik Poike and another adult male inside the house.

Police have not identified the adult male but all three victims had gunshot wounds.

Tran lived in the home's basement and allowed the victims to live on the home's main floor, but Chipping didn't know if they paid rent as formal tenants or had some other arrangement.

Chipping said police don't know when the deaths occurred but the bodies were discovered after Heike Poike's 8-year-old grandson wasn't picked up from elementary school on Friday.

"Grandma was supposed to come pick up him up and after school had ended and nobody showed up for him, the school started trying to find somebody," Chipping said.

When officers arrived at the home where the boy's grandmother lived, they looked through a window and saw what appeared to be a body covered by a tarp. They went around to the back of the home and found an open door, Chipping said.

Officers called out to see if anyone was inside and when they entered, they discovered Tran inside the home with a gun, he said.

Police took Tran into custody and then discovered the three bodies inside.

Chipping didn't have details about how many gunshot wounds each of the victims had or Tran's behavior when police encountered him.

When police questioned Tran, he admitted to detectives that he was responsible for the deaths, according to jail documents released Saturday evening.

Police on Saturday booked Tran into the Salt Lake County jail on suspicion of three counts of aggravated murder.

Chipping did not know if Tran had an attorney Saturday.

Investigators don't know of any further relationship that Tran may have had with the family or any motivation for the shootings, Chipping said.

Police believe the 8-year-old boy lived in the home as well.

Chipping didn't have details about the boy's parents or other family members but said the boy on Saturday was with relatives.

Chipping said investigators were not looking for any other suspects but asked that anyone with information about the case to contact police.