What happened to the perfect child? One woman's incredible story

"She was a beautiful child," Crystal said.

"We did see the anger, but it could be explained," Crystal said.

But soon enough, Crystal and Jesse said Caralee started acting withdrawn and angry.

She suddenly heard her 4-year-old son screaming and when she looked over, Crystal told "48 Hours" correspondent Troy Roberts she saw Caralee holding Joshua over the railing of the 30-foot-high deck. .

"Her face, there was anger and hate," Crystal explained to Roberts.

Crystal demanded Caralee put her brother down and asked what she was doing.

"'I'm gonna kill him,' she said.' 'Why?'  Crystal asked her daughter.

This was all critical information that Crystal and Jesse said the adoption agency failed to share with them beforehand.

She denied hiding any information from Crystal and Jesse, and explained that the medical information she received was limited by Russian privacy laws.

After almost four months away in therapeutic care, Crystal and Jesse had to bring Caralee home after their insurance started running out.

"She has repeated this for months on multiple occasions, 'if I get another chance, I will kill him,'" Jesse said.

"Why do we have to send him to grandma's house to keep him safe?" Crystal asked Caralee.

After treating Caralee during her stay at the psychiatric hospital, this doctor wrote, "Caralee's behavior … was impeccable," and that his staff perceived Crystal and Jesse as "too often cool and distant" towards their daughter.

After they arrived in Moscow, Crystal and Jesse arranged for Caralee to stay at a children's psychiatric hospital.

But right before she went in, Caralee told "48 Hours"' Troy Roberts something she had never said before.

"I did not try to kill my brother," Caralee explained.

Despite what she told Roberts, Crystal and Jesse felt they had done everything they could?

"I don't feel safe here," Caralee told Roberts.

When Sabrina was living with Crystal and Jesse, she said it seemed like they favored Joshua over her, which made her feel unwanted.

"I told Crystal, 'You know, I'm seeing and hearing things,'" Sabrina said.

When Crystal asked her to go and get Joshua, Sabrina said she struggled to carry her brother down the stairs because he was too big and sliding out of her hands.

Sabrina said she tried to explain this to Crystal.

You were trying to kill him.' And she kept saying it," Sabrina told Roberts.

And after Crystal and Jesse left her at the hospital in Moscow, Sabrina said she knew they weren't coming back for her.

Sabrina also says she loved Crystal and Jesse when she was a child

"I wouldn't … take a child back," Sabrina said