Huntsman, 39, told police she either strangled or suffocated them immediately after they were born. She wrapped their bodies in a towel or a shirt, put them in plastic bags and then packed them inside boxes in the garage of her home south of Salt Lake City.
What's not clear is why. A day after her arrest on charges of killing her six babies, investigators and her neighbors puzzled over the grisly discovery, including how she could have concealed a half-dozen pregnancies over a 10-year period.
"How can you have a baby and not have evidence and other people know?" asked neighbor SanDee Wall. "You can't plan when a baby is going to come. Just the thought of somebody putting a baby into a box is a heartbreaker."
Huntsman, who was arrested Sunday on six counts of murder, was ordered held on $6 million bail - $1 million for each baby. The remains of a seventh baby police found appears to have been stillborn, authorities said.
According to a probable cause statement released by police Monday, Huntsman said she gave birth to at least seven babies between 1996 and 2006 at her former home in Pleasant Grove, a leafy, sleepy town about 35 miles south of Salt Lake City.
All but one of them was born alive, she said.
Her estranged husband, Darren West, made the discovery Saturday morning while cleaning out the garage of the house, which is owned by his parents. He called Huntsman, who admitted to him it was her baby, according to court documents.
West called police, who then found the bodies in the garage.
Investigators believe Huntsman is the mother of them all based on what she has told them but have ordered DNA tests to make sure that's the case. Huntsman's three daughters - one teenager and two young adults - also lived in the house.
It could take weeks to get the results, Utah County Attorney Jeff Buhman said.
Investigators believe West and Huntsman were together when the babies were born, but don't believe he was aware of the killings. Buhman said Huntsman is the principle suspect, but didn't rule out more arrests as the investigation continues.
Police declined to discuss whether West or the three daughters have been interviewed.
West pleaded guilty in federal court in 2005 to two counts of possessing chemicals intended to be used in manufacturing methamphetamine, according to court records. In August 2006, he was sentenced to 9 years in prison, but appealed three times.
As he maintained his innocence, Huntsman wrote a letter asking a federal judge to consider leniency at sentencing.
"Darren is a remarkable man, husband, brother, son, son-in-law, friend and father of our three beautiful daughters," she wrote, continuing, "Please we need this guy to keep our family together."
Neighbor Sharon Chipman said the couple married young, and Huntsman never worked except for a short stint at a grocery store.
The three daughters who were living in the house were good young women who have turned out remarkably well considering their father has been in prison, Chipman and Wall said.
West's parents have played an influential role in their upbringing, especially the youngest, who is still in junior high.
Wall said she's puzzled about why Huntsman would have killed the babies, especially considering her youngest daughter, now a young teen, was born during the decade Huntsman told authorities she killed the other babies.
"Why was one of them saved?" Wall said.
Like all states, Utah has a safe haven law that allows women to drop off unwanted newborns to authorities with no questions asked. The mother can remain anonymous as long as the child has not been subject to abuse or neglect.
In coming days, defense attorneys for Huntsman are likely to closely examine her background to search for any evidence of mental illness or a family history that would help explain the alleged killings, said George Parnham, who represented Andrea Yates, the Texas woman who drowned her five children in her bathtub in 2001.
Defense attorneys also will try to determine whether Huntsman sought an abortion and if she told anyone about her pregnancies - all in hopes of understanding actions that otherwise appear incomprehensible, Parnham said.
"You start off with the very nature of what happened. Is there a rational motive?" he said.
Associated Press writers Michelle Price in Salt Lake City and Matthew Brown in Billings, Mont., contributed to this report.