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The Manhattan mother of two young children found fatally stabbed in their tony Upper West Side apartment maintained a blog of her children, detailing the “precious hours” she spent with them.

Marina Krim returned to her West 75th Street home about a block away from iconic Central Park at about 5:30 p.m. Thursday with her third child after nanny Yoselyn Ortega, 50, failed to meet her for swimming lessons with Krim’s two other children, Leo, 2, and Lucia, 6. When she entered the apartment’s bathroom, the children were already dead in a bathtub and Ortega stabbed herself, Police Commissioner Raymond Kelly said Friday.

“Something happened to my kids!” screamed the sobbing mom, who wrapped the nanny’s neck with a towel.

Doorman Glen Loody told the New York Post he heard the distraught mother's cries and called 911. “She was crying. She was screaming,” he said.

Ortega remained intubated and hospitalized in critical condition Friday in Manhattan, said Kelly, adding that detectives have yet to speak with her. Ortega, who has no known criminal record, had not been charged.

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“It’s difficult to say,” Kelly said as to when Ortega would be charged. “Obviously that depends on [a] doctor’s determination. She does have cuts to wrists and to her neck.”

Ortega, a naturalized U.S. citizen originally from the Dominican Republic who has been in the country for a decade, had been working for the Krims for two years and was referred to them by another family, Kelly said.

Detectives on Friday continued to process the apartment and Ortega’s purse, Kelly said. Ortega, also of Manhattan, did not live with the family. Kelly said Ortega had no known history of mental illness, but said investigators were probing unconfirmed reports that she recently saw a psychiatrist.

“There’s no history that we’re aware of,” Kelly said. “Obviously, this investigation is ongoing.”

Krim, who was a stay-at-home mother until a year ago, kept a loving online journal of her children’s lives, including apple-picking trips, family vacations and strolls down Broadway, the Post reported.

In Krim’s latest entry — posted to “Life with the Little Krim Kids” just three hours before finding Lucia and Leo dead — the loving mom wrote about her son learning to put words together.

“Leo speaks in the most adorable way possible,” Marina Krim wrote, describing her mood at the time as “amused.”

In February, Krim wrote about visiting their nanny’s family in the Dominican Republic. Krim referred to the woman as Josie. It’s unclear whether it’s the same woman found wounded Thursday.

"We met Josie's amazing familia!!! And the Dominican Republic is a wonderful country!!," she wrote.

Another entry in May detailed Leo’s obsession with his new Crocs.

"Even at nap time — Josie, our nanny, took them off and he screamed bloody murder, so she put them back on and he went right to sleep," Krim wrote.

Marina and her husband Kevin were extra careful in hiring and vetting Ortega, even spending nine days with her family in the Dominican Republic prior to her hiring, according to friends.

“Kevin told me that she was a nice girl,” the children’s paternal grandmother, Karen Krim, told The Post. “How could she do something like that? The children were angels.”

Ortega’s niece, Katherine Garcia, 28, said her aunt had seemed a little off and was “acting kind of nervous lately.”

“This is just shocking,” she told the newspaper. “She loved those kids. I don’t know what would make her do this.”

Kevin Krim, a CNBC executive, was returning from a business trip to San Francisco and was notified of the horrific killings once he arrived in Manhattan last night, a source said. Police then took him to St. Luke’s Hospital, where Krim had to be sedated. The couple’s third child, Nessie, 3, did not witness the carnage at her home.

Originally from the West Coast, the Krims moved from San Francisco to New York a few years ago. Neighbors described the young family as happy and loving.

“It’s horrifying,” said one resident, who met the nanny for the first time Wednesday. “She was very quiet — she just stared ahead.”

The couple’s three children had participated at their aunt’s wedding just last month, with Leo acting as a ring bearer and Lucia and Nessie serving as flower girls.

“I just don’t understand,” another neighbor said. “It’s so senseless. A nanny would be the last person I’d think would ever do something like that. I’m in shock. Total disbelief.”

Fernando Mercado, the superintendent of the building where Ortega lives with her sister and niece, told The Wall Street Journal that she is "a very nice woman" and "very religious."

"To me, she has always been very, very stable," Mercado said.

Comcast and NBC Universal officials said the sadness felt for the Krim family is "without measure," according to a statement issued Friday.

"A member of the CNBC family has suffered an unimaginable loss," the statement read. "The sadness that we all feel for Kevin, Marina and their family is without measure. Our thoughts, prayers and unwavering support are with them all."

FoxNews.com's Joshua Rhett Miller and The Associated Press contributed to this report.