A beautiful family experienced unimaginable tragedy when a trusted nanny killed two of the family's children.

On Oct. 25, Marina Krim returned to her Upper West Side apartment in New York in the evening to find both of her children dead in the bathtub at the hands of her nanny bleeding nearby.

Krim's 2-year-old son Leo and 6-year-old daughter Lulu were found stabbed and bleeding to death in the bath along with 50-year-old nanny Yoselyn Ortega nearby who failed to kill herself by slitting her own throat.

Marina arrived at her Manhattan home with her three-year-old daughter Nessie who was with her at the time of the attack, according to the New York Post. The mom of three returned to her home after Ortega and the two children were missing from meeting Marina and Nessie at a nearby pool.

Doorman Glen Loody told the Post that he heard Krim's agony and called emergency services. "She was crying. She was screaming," he said.

Ortega is in police custody after her failed suicide attempt. She was found with her throat and wrists cut in the bathroom with a kitchen knife nearby. The nanny was brought to New York-Cornell Hospital and police said as of Friday morning that she remains in a stable condition.

According to Kevin's mother, Karen, the family hired the nanny from the Dominican Republic a year ago and said she had no criminal record.

"Kevin told me that she was a nice girl," the grandmother told the New York Post. "How could she do something like that? The children were angels."

Authorities are looking into Ortega's past to try and find a reason why she committed the murders. The nanny did not live with the family.

"There's no history that we're aware of," Police Commissioner Raymond Kelly said Friday. "Obviously, this investigation is ongoing."

Marina works as a pediatrician and her husband Kevin is the senior vice president and general manager of CNBC Digital. Kevin was on a business trip at the time of the incident and was met by police upon his return.

Marina loved her family and kept a detailed blog with many pictures of her kids.

One blog entry states:  "One of the best parts of my day is after I drop both girls off at school and have 3 precious hours with little Lito all to myself. Ok, I'm near getting cheesy I adore this boy so much!!!"

Krim Family: Marina and Kevin Krim Receive Outpouring of Support After Nanny Yoselyn Ortega Murdered 2 Children [PHOTOS]