Yoselyn Ortega murdered 6-year-old Lucia Krim and 2-year-old Leo Krim inside their apartment on October 25, 2012. She learned her fate after emotional impact statements by the victims' parents.
Mother Marina Krim told a judge that Ortega instead destroyed her own family. She said Ortega has shown no remorse, and no one in her family has ever said they were sorry.
"The defendant may think she destroyed Lulu and Leo, but she is a failure in this, too. Lulu and Leo are powerful forces," she said through tears. "They are two stars now who will always lead us forward."
Marina Krim and her husband, Kevin Krim, spoke of how Ortega's family and friends helped with this by lying to them about Ortega's personality and experience as a nanny. Ortega, who's from the Dominican Republic, had been recommended by her sister, a nanny for another New York family, and her background and references were faked by her family. The consequences, the Krims said, were horrifying.
"We miss hearing them call out my name and run to hug me when I got home from work," Kevin Krim said while crying. "We miss feeling their soft skin in our arms."
Ortega also spoke briefly.
"I'm very sorry for everything that happened, but I hope that no one goes through what I have gone through," the 55-year-old Ortega said through tears. "Although many people wish me all the worst, my life is in the hands of God."
Ortega said she wasn't feeling well but wasn't able to go to the doctor.
"I ask for a great deal of forgiveness," she said. "To God, to Marina, to Kevin. I wish my family had told them that I did not feel well."
Judge Gregory Carro referred to Ortega as "pure evil" and said she should spend the rest of her life in prison.
Kevin Krim eviscerated Ortega for not pleading guilty and forcing the case into a courtroom. He said she never should have put the family, the jurors or the audience through it.
"The defendant is an evil and utterly dangerous narcissist," he said. "It is right that she should live and rot and die in a metal case, like the ugly and dark shadow of Lulu and Leo's bright and shiny lights."
Ortega was sentenced to life in prison on two counts of first-degree murder and consecutive sentences of 25 years each on two counts of second-degree murder. She was convicted last month after her lawyers argued she was mentally ill and couldn't be held responsible for their deaths.
Prosecutors say Ortega knew what she was doing and understood "every stab, every slash" as she slaughtered the children.
During the seven-week trial, jurors grappled with whether Ortega had been too mentally ill to understand what she was doing when she killed the children. The emotional testimony often kept the panel and the audience in tears. Jurors heard heart-wrenching testimony from Marina Krim, who spoke of coming home to her eerily quiet apartment and finding her children covered in blood in the back bathroom.
Krim had been at a swimming class with her 3-year-old daughter, Nessie Krim. Ortega was to have dropped off Lucia at her dance class, and Krim was to pick her up. But when they arrived, Lulu wasn't there. Krim frantically tried to reach Ortega, who had worked for the family for about two years.
Krim opened the door to the bathroom to discover the children's bodies stacked in the tub. Lulu was stabbed more than 30 times, and Leo was stabbed five times.
Ortega had cut her own throat in a failed suicide attempt.
At the sentencing, Marina Krim talked about what that crime scene may have done to Nessie, even though she has grown into a strong, happy child.
"As Nessie grows up, she will be asking Kevin and me deep, unanswerable questions about life that most parents avoid talking about with their kids," Marina Krim said. "But we will try to answer her questions with sensitivity the best we can."
At Ortega's trial, Kevin Krim, who had been on a business trip and received news of the children's deaths when his plane landed, spoke of walking down a long hallway at the hospital where he saw their bodies.
Prosecutors argued that Ortega was jealous of Marina Krim's life and lashed out in the worst way possible, at her children.
The Associated Press contributed to this report.