(CNN) -- A grand jury indicted the nanny of two young children found stabbed to death in the bathtub of their Manhattan apartment for their murders, court documents show.
Yoselyn Ortega, 50, was arrested earlier this month and charged with the murders of Lucia Krim, 6, and her brother Leo, 2.
Court documents released Tuesday show the grand jury indicted Ortega on first- and second-degree murder charges in both deaths.
Police say on October 25, the children's mother, Marina Krim, returned to the family's Upper West Side apartment, found Lucia and Leo dead in the bathroom and saw the nanny stab herself with a kitchen knife.
Ortega has been recovering since then at Weill Cornell Medical Center under police watch, and was still there as of Tuesday, according to hospital spokeswoman Linda Kamateh.
Krim left two of her children with the nanny to take her 3-year-old child, Nessie, to a swim lesson at a nearby YMCA, New York Police Commissioner Ray Kelly said last month. She had expected to meet the nanny around 5:30 p.m. at a dance class, but when Ortega failed to appear she went back to the apartment.
The late children's father is Kevin Krim, a senior vice president for CNBC Digital and former Yahoo executive.
A native of the Dominican Republic, Ortega had been a naturalized U.S. citizen for 10 years.
Friends had introduced the family to Ortega, and she had worked for them since Leo's birth two years ago, police said.
Ortega was not a live-in nanny, but Marina Krim's blog, "Life with the Little Krim Kids," offered the loving mother's view of a family life that included Ortega as a member.
In February, the Krims traveled to the Dominican Republic, where they met Ortega's family.
"We spent the past nine days in the Dominican Republic," Marina Krim wrote on February 18. "We spent half the time at our nanny, Josie's sister's home in Santiago and the rest at Balcones de Atlantico in Las Terrenas, a condo-style hotel where the 'Real Housewives of Dominican Republic' and their families hang on weekends. It was wonderful."
She added, "We met Josie's amazing familia!!! And the Dominican Republic is a wonderful country!!"
One photograph showed the families together, Ortega holding the girl who was learning how to swim at the time her siblings were killed.
CNN's Kristina Sgueglia contributed to this report