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BENBROOK (CBSDFW.COM) – A murder mystery involving a Van Cliburn award winner… two children, a baby and her kindergarten-aged sister, murdered… and a mom left fighting for her life took another dramatic turn today.

The children’s mother, Sofya Tsygankova, 31, was charged with two counts of first-degree murder, according to officials with the Benbrook Police Department who interviewed her from her hospital bed.

“We have probable cause to believe she committed these homicides,” police said during a Monday afternoon press conference.

Police also said Tsygankova’s stab wounds were self-inflicted and they had collected physical evidence at the scene of the tragedy.

The case began when the dead children of world famous pianist Vadym Kholodenko were found in the family home, in the 6600 block of Waterwood Trail. Kholodenko’s wife, Tsygankova, was also inside the house and has suffered multiple stab wounds.

Initially it wasn’t known who contacted police, but during a press conference Benbrook police Commander David Babcock cleared that up. “Mr. Kholodenko was the person who initiated the 911 call yesterday morning at 9:27 a.m. He had an appointment with the mother of the children to pick up the children at 9:20 a.m., which was their regular practice as far as we can tell.”

Commander Babcock said that once inside Kholodenko, a Ukrainian native and Fort Worth Symphony Orchestra Artistic Partner, was distressed by what he saw. “Once he arrived there he found the mother in an extreme state of distress and discovered the children in their state.”

The girls were found in their bedrooms with no visible physical injuries.

Police say Kholodenko, the gold medal winner of the Fourteenth Van Cliburn International Piano Competition in 2013, has been “cooperating in this investigation and is not considered a suspect.”

Tsygankova was placed on mental evaluation while recovering at the hospital.

According to court records, Tsygankova and Kholodenko were in the middle of a contested divorce. Benbrook police did say that it wasn’t the first time they had visited the home on Waterwood Trail. Cmdr. Babcock said, “We made two calls to the residence in 2014. I’m not going to disclose the nature of those calls at this point.”

Neighbor Terry Messer said Tsygankova, also a pianist, spent a lot of time parenting alone. “She was a stay at home mom with two children. Her husband was gone a lot… seemed to travel. She was very lovely. She was a Russian immigrant [and] she spoke Russian to the children a lot.”

Kholodenko has played with the Atlanta, Eugene, and Hawaii Symphony Orchestras, and also with the Royal Philharmonic Orchestra. He was scheduled to play at Bass Hall tonight.

Messer said she had a brief, but touching reminder of the little girls who lived next door. “The children wrote on my driveway — their names in hearts. It was there until this [Thursday] morning, when the rain washed it away.”

CBS gave viewers a new glimpse into the lives of the Kholdenko sisters from a swim coach who taught the oldest daughter private lessons.

“I’m at a loss for words for what could have happened,” said Rachel Capper. “It’s heartbreaking.”

Capper spent an entire summer working with the oldest daughter Nika, 5.

“She always talked about how her dad was a piano player,” said Capper. “It was always kind of sweet.”

Capper met with Nika’s mother Sofya on many occasions. She said the two would discuss the lessons and Capper would give updates on how Nika was progressing as a swimmer.

“She always seemed very disappointed,” said Capper. “She always was kind of like, what can I do to make her better… how can I make her perfect at this.”

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