Family members of a Utah woman sentenced to the maximum penalty Monday for killing six of her newborn babies said they were shocked at the grisly crimes from the woman they knew as a loving mother.

Her family painted 40-year-old Megan Huntsman as a shy, timid person who struggled with addiction and depression but was a good mother to her three other children.

Judge Darold McDade sentenced Huntsman on Monday to up to life in prison in what prosecutors called indifferent and callous actions committed because she was too addicted to methamphetamine to care for more children during the decade when the babies were killed and stored in her garage.

Police said she concealed her pregnancies, gave birth at home, and choked and strangled the children with her hands just minutes after they were born. She killed six babies, and a seventh body of a newborn was found to be stillborn.

Huntsman didn't speak at the hearing, but her lawyer read a statement.

"I know I didn't feel strong enough to be a mother to those tiny babies, and in some small way I wanted to help them avoid the terrible life I would have given them," said Anthony Howell, reading from a letter she wrote. Huntsman said she couldn't explain the deaths to herself.

Family members sobbed in the courtroom as Pleasant Grove Police Detective Dan Beckstrom testified about the killings.

He said the first body was discovered by one of the couple's daughters as she cleaned out the garage with her father, Darren West, shortly after he finished an eight-year federal prison stint on meth charges in April 2014. He lived with Huntsman during the decade when the babies were killed, but police have said they aren't investigating him in the deaths.

Police found the bodies wrapped in cloth, put in plastic bags and packed into boxes, left behind after Huntsman moved out. She thought about moving the bodies, but she said she couldn't think of a way to do it without getting caught, said Prosecutor Jeff Buhman.

It remains unclear how Huntsman concealed the pregnancies, births and murders from family members and friends. She gave birth at home, twice when other people were in the house, and made sure the rooms were clean and the bodies packed away before anyone knew what was happening.

Over the years, she could smell their decomposing bodies in the garage but never moved them, he said.

"These were very cold, calculated killings," Buhman said. "She was a woman who was remarkably, unbelievably, incredibly indifferent and callous."

The description contrasted sharply with her family's image. Sister Jamie Huntsman read letters from two of Huntsman's other children, who described their mother as smiling and laughing.

"This is not the mom I know," she read. "I remember the mom I know, the one that made dinner for us every night, cleaned our house and loved not only her kids but kids in general."

West spoke briefly to reporters outside the courtroom Monday, saying the details about the babies' deaths were difficult to hear.

Huntsman agreed to plead guilty rather than go to trial under an agreement that reduced her minimum possible sentence to five years but left fewer options for appeal. Prosecutors said it would have been hard to prove the case against her at trial if she hadn't cooperated with police.

McDade departed from that deal Monday, giving Huntsman a longer minimum sentence.

"I really thought I'd seen it all until this case came along," he said.

A parole board will make the final decision on how much time Huntsman spends in prison.

The sentence brings closure to a case that shocked residents of Pleasant Grove, the mostly Mormon community about 35 miles south of Salt Lake City.