The autopsy revealed the baby had been completely healthy - no diseases, no injuries, no genetic abnormalities, police records state. She died from lack of oxygen.
As police considered the facts of the child's death, something caught their attention and ultimately spurred a hushed investigation: it wasn't the first time LaFountain had lost a child this way.
LaFountain, 23 - who says she has changed back to her maiden name, Bilecki - was indicted last Thursday in the deaths of her two infant daughters, two years apart. She has been charged with murder in the first and second degree in both cases.
She was arrested on Friday and is being held at Fairbanks Correctional Centre. The maximum sentence for first degree murder in Alaska is 99 years in prison and a fine of up to US$500,000.
When LaFountain's 4-month-old died on September 15, 2015, police thought it was an accident, an isolated tragedy. As she did with the 13-month-old, LaFountain called emergency responders and said the baby had stopped breathing.
She also called family members. The infant, whose father was from a previous relationship, died later that day. The cause of death was undetermined, according to police records, but the body showed signs of suffocation.
The commonalities in the two deaths, and the short time that separated them, were part of what led investigators to believe they'd been murdered, Fairbanks Police spokesperson Yumi McCulloch said.
"First it was just pulling up her name in the system and saying, look at that, there was another one," McCulloch said. "And then in both circumstances she called saying the child wasn't breathing, she called the family."
A lawyer for LaFountain could not be immediately located.
At a news conference, Fairbanks Police Chief Eric Jewkes questioned what true justice might look like in the wake of such unspeakable tragedy.
"We have two babies that were killed by their mother. How do we even imagine that," Jewkes said. "There's nothing we can do to make this right."
He praised the detective who spent thousands of hours working the case, while working in a five-person department that handled several other homicide cases during the course of the investigation. Because of its sensitivity, the case - which involved techniques that have never before been used in the US - was kept quiet, Jewkes said. He thanked the families of the dead infants who had to mourn in secret during the nine-month investigation, and said he hoped police could find a way to bring them closure.
"We have a family of a baby that has suffered in obscurity, in silence," Jewkes said. "They were all alone."
Investigators are not ready to release any information about LaFountain's possible motives or other details of the investigation, McCulloch said. They also haven't specified how they ascertained that LaFountain had conducted the internet searches for suffocation and murder.
According to her LinkedIn page, LaFountain had been working in the deli department at a Fred Meyer grocery store since 2011. She was divorced in February, according to online court records, and has no other children. Detectives do not think her ex-husband, the soldier and father of the 13-month-old, had any prior knowledge of the crime. He's considered a victim in the case, according to reporting from NBC News.
