MARIETTA - Brittiany Young, of Kennesaw, testified Wednesday in Cobb Juvenile Court that when she returned to her car in the Target parking lot off Dallas Highway after shopping for 18 minutes, she saw her 5-week-old daughter not breathing and with blue, swollen lips.

"What did you do to her? What did you do?" she remembered asking her then-11-year-old cousin, who was visiting from Tampa, Fla., and whom she had left her infant daughter with inside the car.

"Nothing," Young recalled the boy saying.

The boy - who is now 12 and not being named because he is a juvenile - is charged with felony murder and cruelty to children in the death of his infant cousin, Millan Young.

The first day of the non-jury trial started Wednesday. The long day of testimony ended about 10 hours later with Poole throwing out sections of interviews police had with the juvenile. Poole is expected to hear key medical evidence today.

The tragic incident occurred on July 4. The juvenile was in Cobb County staying with relatives. Young testified Wednesday that she left her daughter and the boy alone her 1998 Honda Accord while she went into the store for food before they went to a party.

The infant died the next day at a hospital. An autopsy showed she had multiple skull fractures and died of blunt force trauma to the head, officials said.

After she got back inside the car and was pulling out of the parking space, Young testified that she noticed something was wrong with her daughter.

"She was blue," Young told the prosecutor after breaking down and crying. "Her eyes and mouth became swollen and was hard to the touch. I noticed she had a little bleeding to the mouth."

Young said she told her cousin to call 911, which the boy did with his cell phone, while she got out of the car and checked the infant. She said first responders arrived shortly at the scene and administered CPR and oxygen. The infant was stabilized before being rushed to WellStar Kennestone Hospital. The infant was later flown by helicopter to Egleston Children's Hospital in Atlanta.

Several paramedics who responded - including a Kennesaw Mountain National Battlefield Park ranger - were called by the prosecution to testify about details of their medical actions that day. They testified that they had found the infant without a pulse, with swollen lips, bruises and a spot of blood near her nose.

It was at Egleston the next day that Young said doctors told her that her daughter was essentially brain dead, and she agreed to take her off life support.

During the trial Wednesday, the 12-year-old, dressed in a gold-colored suit, showed little to no emotion as he sat next to his Atlanta lawyer, Derek Wright. His parents and great-aunt sat behind him, at times crying during testimony. Young did not stay in the courtroom after testifying.

The boy and his infant cousin were the only two people inside the car on July 4. It was the boy's story of what took place during the 18 minutes that prosecutors and defense lawyers grappled with Wednesday.

The boy repeatedly told police that the infant was crying in her car seat and that he gave her a pacifier and a bottle. When she continued crying, he said he turned the car's radio volume up, which resulted in her becoming quiet. However, lead Cobb Police Detective Dennis Ryan testified that a doctor told him that the infant's injuries were very recent.

Video was shown to the judge by prosecutor Eleanor Odom of interviews that Cobb police detectives did with the boy and his mother, Camille Curtis, who was in Tampa at the time of the infant's death. His father, Gerado Davis, was away on military duty at the time.

At first, the boy told detectives that he didn't know what happened to the infant. However, his mother later told the detectives that her son confessed to her that he had tried to help the infant when she started chocking after he gave her the bottle, but then dropped her inside the car, which was an "honest mistake."

That didn't sit well with Poole after he viewed additional interview video of the boy repeatedly telling detectives over two long days of interviews that he didn't want to talk to them, yet they continued questioning the boy to approximately midnight July 6.

"He is scared to death," Poole told the lawyers before denying the sections of the interviews as evidence. "How many times does this kid say, 'I don't want to talk to you?'"

Odom typically prosecutes adults in Cobb Superior Court. She said in her opening statement that the infant's head was "bashed in" and that "pictures don't do it justice."

Wright, in turn, argued in his opening statement that this is a case in which "people jump to conclusions." He said there was no evidence found that leads to blunt force trauma causing the death of Millan Young. The injuries will lead to a different conclusion than what the prosecution says, Wright stated.

If convicted of murder, the boy could be sentenced to a detention center until he turns 21, District Attorney Pat Head has said. Head was present at times during the trial.

The trial is scheduled to resume at 9 a.m. today with medical testimony.