While her motive still remains unclear, new details have emerged about the life of alleged "killer nanny" Yoselyn Ortega, who is accused of stabbing two children, 2-year-old Leo and 6-year-old Lucia Krim, to death in a horrific crime on Manhattan's Upper West Side. According to a report in the New York Times, Ortega had become increasingly stressed and unstable in recent weeks.

The NYPD's chief spokesman, Paul Browne, said family members told police that Ortega "over the last couple of months was not herself," and noted that there were reports she had been seeking professional help.

Juan Pozo, a former neighbor, who spoke to Ortega's sister on Friday, said that, lately, "(Ortega) felt like she was losing her mind." He also said she had seen a psychologist recently.

Ortega's sister, Celia, told the New York Daily News she'd referred her sister for the job with the Krims, a fact which left her devastated. "I would like to die. I would give my life for the children to come back," she said.

Several neighbors mentioned Ortega's financial concerns. Earlier this year, she'd moved with her teenage son from her sister's apartment in Harlem to a place of her own in the Bronx. But the person she'd been renting the apartment from, an acquaintance who'd relocated to the Dominican Republic, returned several months ago, forcing Ortega to move back in with her sister. A neighbor said the move occurred after Ortega had already "spent a lot of money on the Bronx apartment." Ortega had also starting selling cheap jewelry and makeup in her spare time.

Another neighbor in Harlem said that in recent weeks Ortega appeared to be "kind of devastated" and was "in bad shape." They also noted that she would regularly work 12 hour days. "I am tired," the neighbor remembered her saying. "Work."

Even with Ortega's increasing personal problems, her relationship with the Krims remained positive.

A law enforcement official said Ms. Ortega had had no previous brushes with the law, nor have detectives learned of any tensions in her relationship with the Krims.

"No fighting with the mom, the family, the kids," the official said. "Everybody is looking for a reason here." He added, "We've got nothing bad other than the fact that she killed two children."

In an interview with the New York Daily News, one of the victims' grandmother, Karen Krim, echoed those sentiments.

"My daughter-in-law, if she thought there was anything wrong, she would have never left the two with her. This had to be something simmering inside this woman. Obviously, she went insane."

The Times also interviewed one of the Krim's neighbors, Charlotte Friedman, who may have been the last person to see the children alive. She shared an elevator with Ortega and the two children late Thursday afternoon.

She asked the girl if she had been on a play date. The child replied that she had been dancing. Ms. Friedman described the girl as "happy, happy, happy."

The times she had encountered Ms. Ortega, she found her cold. There in the elevator, she said, the nanny smiled but said nothing. And then, she and the children got off on the second floor.

[Image via Getty]