Arianna Hunziker was a chubby and happy toddler before she went into foster care, where she lost 10 pounds in about a year and died while wrapped in bed sheets closed off in a room alone.

Foster parents Sherrie Dirk and her husband, Bryce Dirk, each pleaded guilty to one count of second-degree unintentional murder in the 3-year-old's 2017 death. They were sentenced Tuesday after strong rebukes from Arianna's paternal grandparents.

"What the Dirks did to her is incomprehensible to me," said her grandmother, Mary Egan. "I can't imagine the horror [Arianna] went through during these episodes."

Sherrie Dirk, 35, was sentenced to 32 years in prison. Bryce Dirk, 33, was sentenced to 12½ years.

Both originally faced a count of first-degree murder, which was dismissed as part of their plea deals.

Neither gave a statement in court when given an opportunity to speak before their sentencings, which were held separately.

The Dirks became foster parents to Arianna and her older brother after the children were taken away from their biological parents, and had them for about 16 months, said Arianna's grandfather and Egan's husband, Thomas Hunziker. Sherrie Dirk is the children's maternal aunt.

The Dirks withheld food from Arianna and her brother, causing her go from 35 to 25 pounds by the time she died on Nov. 6, 2017.

Sherrie Dirk had wrapped her in sheets and left her in a room for hours. Bryce Dirk called 911 about 6:30 p.m. Police found Arianna unresponsive, "severely dehydrated" and with one sheet around her neck, according to authorities.

The Dirks' four children were removed from their home after Arianna's death.

Sherrie Dirk's plea deal called for a prison term between 25 years and 35 years due to three aggravating factors: Arianna was particularly vulnerable, Dirk was in a position of authority and Dirk left her alone in a weakened state caused by Dirk's actions.

"She deserves the full 420 months," Thomas Hunziker told the court before the sentence was handed down.

Mary Egan told the court her granddaughter was a "loving, happy kid."

Assistant Hennepin County Attorney Erin Lutz said Arianna's neglect was drawn out.

"Arianna was subjected to hours [of abuse] over the course of weeks and months," Lutz said. "She didn't grow for a year in height or head circumference."

Sherrie Dirk's attorney, Robert Kolstad, argued that 25 years was sufficient, and that a history of abuse by a parent and significant others affected her actions.

"A life of tragedy and abuse leads to, sometimes, bad parenting," he said.

Kolstad stressed that there was no indication that she was more culpable than her husband, yet the prosecution agreed to give Bryce Dirk a much shorter prison term. (The term is within state sentencing guidelines for the crime.)

Court records show that Bryce Dirk pleaded guilty before his wife and agreed to the sentence "contingent on truthful testimony in all future proceedings."

Egan said in her victim-impact statement that Bryce Dirk said Arianna had been "acting up a lot" in the weeks before she died and that "we" were swaddling her. Egan added that she believes he participated in the swaddling.

The children had been in Egan and Hunziker's care before the Dirks became their foster parents. Egan said she alerted the county after Sherrie Dirk's relatives warned her that she was an unfit parent, but the county seemed to ignore her. A Hennepin County spokeswoman declined to comment, citing privacy concerns.

"I've never suffered grief in this way," Egan said. "She did not deserve to die, and she did not deserve to die the way she did."

When Bryce Dirk was sentenced later Tuesday, Egan and Hunziker told the court that he was just as culpable as his wife.

"Mr. Dirk certainly could have given [Arianna] a cup of water," Hunziker said. "He certainly could have given her some food. Her certainly could have objected."

Hunziker added that as Arianna was wasting away, the Dirks' daughter, who was two weeks older than Arianna, continued to grow and thrive.

Lutz said prosecutors agreed to give Bryce Dirk a lighter sentence because he cooperated and because his culpability was one of "negligence" rather than an "overt act."

Although defense attorney Jason Steck said his client had a "great deal of remorse," Bryce Dirk did not apologize in court.

"It would be nice to hear some of the remorse he supposedly feels," Egan said. "I'm sure he's remorseful he's going to prison. I'm not sure he's remorseful for what he did to get there."

Hunziker and Egan have custody of Arianna's brother, who they said struggles with post-traumatic stress disorder and severe food issues, among other issues.

"He's very protective of his food," Hunziker said.

Hunziker and Egan said the boy is receiving treatment and is improving.

Staff writer Chris Serres contributed to this report.