By CAROL MARBIN MILLER AND TERE FIGUERAS NEGRETE

The 11-year-old boy was lying on the couch watching his favorite movie, The Black Stallion, when his mother, sobbing after an argument with her estranged husband, went into the kitchen and picked up a knife.

Pointing at his wrist, the boy described what happened next: 'She started doing bad things. I started running, and pushing her to get the knife out of her hands. I said, `You don't have to do this. You have two reasons to fight for.' She was saying, 'I don't care.' ''

The boy, now 13, was the first witness to testify Tuesday at a rancorous custody trial over the fate of his 4-year-old half-sister. The case pits the girl's father, Rafael Izquierdo, a Cuban farmer, against the girl's foster parents, Coral Gables couple Joe and Maria Cubas.

State child-welfare lawyers say Izquierdo, who lives in Cuba, is unfit to raise the girl because, among other things, he did nothing to protect her when their mother, Elena Perez, beat her.

The boy testified that while he and his sister were living in Cuba, he told Izquierdo -- who did not live with them -- that both he and his little sister were frequent victims of their mother's violent moods. If lawyers with the Department of Children & Families can convince Miami-Dade Circuit Judge Jeri B. Cohen that Izquierdo abused, neglected or abandoned his daughter, they will then request that she be allowed to live permanently with the Cubas family.

Izquierdo, who is in the United States temporarily to take part in the case, has said he wants to return to his Cuban village of Cabaiguán with the youngster.

The Miami Herald is not identifying either child to protect their privacy.

ADOPTION AGREED

The boy and his half-sister, who arrived in Miami with their mother and their stepfather in March 2005, were taken into the custody of DCF after their mother attempted suicide. The boy was adopted by the Cubas family after both his mother and father, who remains in Cuba, agreed to the adoption. The stepfather left Perez and has since returned to the island.

The drama began in December 2005 when Perez, living hand-to-mouth, abandoned by her husband and beset by emotional problems, took a kitchen knife to her wrists. Her son testified he begged her to call police before ending her life.

'I started crying, saying `Please stop. Stop,' '' the boy testified. 'I said, `If you do this, please call the police first.' ''

Perez was involuntarily committed, and the state took the children.

Dressed in a blue polo shirt with green and white stripes, his black hair cropped close, the boy was questioned in a small wood-paneled room by an attorney for the Guardian-ad-Litem Program, John O'Sullivan. His testimony was broadcast to a nearby courtroom through closed-circuit TV. Speaking in English, his second language -- though occasionally reverting to Spanish -- the boy said Perez beat him daily for virtually no reason, and beat his sister ``twice a day.''

The teen catalogued the myriad ways in which he said his mother mistreated him and his sister: She hit him. She kicked him while he was on the ground. She pulled the girl's hair. She hit him with a stick. She choked him. What did the girl do to prompt such abuse, O'Sullivan asked him. ''She would cry. She would talk to her back,'' the boy replied.

As the boy spoke, his court-appointed guardian-ad-litem, Andrea Steinacker, gently stroked his back. A few times, she reached over and held the boy's hand.

The teen described one incident in Miami when his mother became enraged that he had inadvertently hit her with a cart he used to throw out the trash.

'She said, `Prepare yourself.' I was nervous because I thought I was going to get beat up. She walked forward and hit me with a stick.''

Throughout most of the boy's testimony, Perez sat at her attorneys' table, her head resting on her clasped hands, eyes down. A half hour after he began testifying, she began to weep and was led out of the courtroom.

During a lunch break, surrounded by reporters outside the courthouse, she tearfully read a poem she wrote as a plea to her son.

''One day you'll understand that a good mother is not an object, a toy, an insignificant thing,'' she read in Spanish. ``One day you'll understand how much I love you, adore you. One day you'll understand.''

Perez said she occasionally spanked her children, or slapped them, but that her actions did not constitute the abuse described in court, calling her son's statements an exaggeration. ''It's all lies,'' she said.

Later in the day, a DCF supervisor testified that his notes about the agency's decision to take custody of the children did not mention any concerns that they were being physically harmed by Perez.

''This was somewhat of a special conditions case,'' said Sam Reynolds, an investigations supervisor who handled the case. Under questioning by Izquierdo's attorney, he reviewed his casework notes, which have been entered as evidence in the case. ``No one alleged abuse under this particular incident that I can recall.''

The DCF attorneys maintain that Izquierdo should have known his daughter was in peril, and was aware of Perez's mental state even before she left the island with the children.

TOLD OF BEATINGS

During the boy's cross-examination by Ira Kurzban, Izquierdo's attorney, the boy said he had told Izquierdo only once while living in Cuba that his mother was routinely abusing him and his younger sister. He said several members of his large extended family in Cuba knew of the beatings, as did his teacher.

After the hearing, Izquierdo told reporters that the boy never told him about any abuse.

At one point during the questioning, Kurzban asked the teen if he thought Izquierdo loved the girl.

''I don't think so,'' the boy replied. ``He didn't pay attention to my sister like I did. He wasn't there when my sister needed him. My sister got hit really hard; he was supposed to be there.''

The boy said that while they lived in Cuba, Izquierdo visited perhaps twice a month.

Questioned by Kurzban about how he feels about his mother, the boy said: ``I don't want to kiss her. I don't want to get close to her.''

Speaking matter-of-factly, the teen later said any warm memories of his mother were few and far between.

''In my life there were little times where she was lovely, she was awesome,'' said the boy. ``But that was really small.''

As the boy's testimony came to an end, O'Sullivan asked him one final question: If ``somewhere in your heart you have love for your mother.''

The boy's one-word response: "Yes.''