A young Cuban girl at the heart of an international custody battle was beaten and abused by her mother, who also threatened to kill herself with a knife, the girl's older half brother told a judge Tuesday.

The 13-year-old boy told Miami-Dade Circuit Judge Jeri B. Cohen that their mother, Elena Perez, also abused him. The boy was the first witness in a trial to determine whether the girl's father, Rafael Izquierdo, is fit to regain custody of her and return to Cuba, or whether she should stay in the U.S. with her foster parents, sports agent Jose Cubas and his wife Maria.

Cohen must decide whether Izquierdo should have known about the abuse and if he failed to protect the girl by letting Perez bring her to the United States legally in 2005. Izquierdo, a farmer, wants to take the girl home to the communist island, but Florida child welfare officials are backing the Cubases. They have already adopted the boy and want to adopt the girl. The battle is sparking memories of the fight over Elian Gonzalez almost eight years ago.

Perez "was always hitting me, beating me up, kicking me on the floor, screaming at me, so I was scared," said the boy. His mother also hit his sister, the boy said. The children's names are being kept secret by both sides.

The boy testified in the judge's chambers with a video feed to the courtroom. The girl has lived with the Cubases for about 18 months and calls them "Mami" and "Papi," they have said.

"I would do anything for my sister to stay here," the boy told attorneys, his voice cracking.

The boy described Izquierdo as "not a bad guy." He said that before they left Cuba, Izquierdo would visit Perez about twice a month after the birth of his sister, occasionally playing guitar with him. He testified he once tried to tell Izquierdo about the beatings with no success. The boy has a different biological father.

"She's giving it hard to my sister," he said he told Izquierdo, terrified his mother would hit him if she overheard. But it was not clear the boy ever said his mother was beating him and his sister.

The boy also said his mother told him she wanted to leave her daughter with Izquierdo when she went to the U.S., but that he refused.

On cross-examination, Izquerdo's attorney questioned how Izquierdo could have known if the alleged abuse was happening. The boy said he told his grandparents, whom he lived with for much of his life, and that they saw some of the beatings. But he also acknowledged that he went to the doctor regularly and never mentioned the abuse and didn't know if his grandparents ever spoke about it to Izquierdo.

The boy described a volatile mother who would beat him for simply spilling a box of detergent. His anguish came through as he spoke of the night she grabbed a knife after a fight with her husband and attempted suicide while his little sister slept in the bedroom. It happened in December 2005 after Perez and the children had moved to the U.S.

"I started crying and screaming 'Please stop. Please stop," he said. "After 25 seconds, I stopped crying and I got angry, and I said 'If you're going to do this, please call the police first."'

The mother did, and afterward, the boy said he was relieved to finally know he would not have to return to her.

After an hour of his testimony, Perez left the room sobbing. Outside the courtroom she later read a letter she'd written to the boy, telling him that one day he would understand that she had only meant to discipline him and that she'd grown up in Cuba thinking it was culturally acceptable to hit a child with a belt.

The custody fight has been called "Elian II" here in Miami. The Cuban boy who was 5 when he was found at sea after his mother drowned during an attempt to reach the U.S. in 1999. He ultimately was returned to Cuba with his father after U.S. agents seized the boy from a Miami home at gunpoint.

But unlike with Elian, all parties in this case have agreed to allow a family court to decide the girl's fate, and unlike the last time, both the Cuban-American community and the Cuban government have remained relatively quiet on the issue.