ALBANY, N.Y. — Calling the boy she killed her "little buddy," Tiffany VanAlstyne spoke publicly for the first time Thursday, since her December 2014 arrest for murdering her five-year-old cousin, Kenneth White.

VanAlstyne, 20, was sentenced to 18 years to life in prison. She had previously admitted the murder in November in Albany County Court as part of a plea deal.

In an emotional statement prepared with help from her attorneys, VanAlstyne spoke about Kenneth and his two young sisters, who lived with Tiffany and others at a trailer home on Thacher Park Road in Knox.

"Those kids meant the world to me, and I loved them very much," she said. "Every day that goes by, it kills me to know what I did ... Kenneth was my little buddy and will always be in my heart."

VanAlstyne also pledged to "do whatever I can to be a better me," and apologized to her family for the pain she caused them.

VanAlstyne, who has been diagnosed as mentally ill according to family court records, was home alone with Kenneth and his two sisters on December 18, 2014. She had previously told investigators that she was wrestling with Kenneth and ended up strangling him for an unknown reason.

VanAlstyne carried the boy's body down the street and dumped it in a snow bank, then reported that Kenneth had been abducted by two masked men in a pickup truck. The ensuing Amber Alert only lasted several hours before investigators learned the truth. Court records indicate VanAlstyne had not taken her proper mental health medications the day of the murder.

Outside court Thursday, Kenneth's mother, Christine White, insisted that she stands by Tiffany.

"I love my son more than anything in this world," White said. "But I also love my niece, and I know what kind of girl she was."

Prosecutors called the case a tragedy on all sides.

"Where are we now, in terms of the health and safety of children in Albany County?" said District Attorney David Soares. "I don't think we've moved the needle. We have a loss of life, and we have the forfeiture of [Tiffany's] future. That's never good."

Others in the community are calling for the criminal probe to continue. The grassroots group Kenneth's Army believes Tiffany's mother Brenda is partially to blame. Brenda VanAlstyne owns the trailer home where Kenneth was killed. Albany County Family Court Judge Gerard Maney declared the home abusive, neglectful and unfit for children at a hearing in 2015.

"I hope and pray that they go for Brenda VanAlstyne next," said Michelle Fusco, one of the founders of Kenneth's Army. "She should be charged. She is just as culpable as Tiffany is."

But the district attorney shot down that possibility.

"This case is over. There is no other case," said Soares. "If the investigation ... was about the health and safety of the other children, for purposes of a family court proceeding, I could see that. But in terms of a criminal prosecution involving the death of this young boy — here we are."

Albany County Sheriff Craig Apple, who had previously spoken about efforts to arrest other VanAlstyne family members, said Thursday that the murder case is closed. He did say that other investigations remain active, though he did not specify what crimes they were related to.

Support continues for Kenneth's sisters. A trust fund for the girls, which was set up by the sheriff's department, had raised more than $20,000 as of Thursday afternoon.