Jurors must decide whether the lawmaker went too far in disciplining his child or whether, as defense attorneys say, it's a changing story by a smart, savvy attention-seeking child.
The victim spent hours on the stand holding a stuffed animal with her grandfather by her side.
"(He) squeezed her face to shut her up to get her to be quiet. Then he smacked her. Smacked her on the sides of the head," prosecutors said.
But the girl didn't talk about the spanking her father claimed she got. Instead, she said she was slapped.
The victim said he squeezed her face then hit her twice. She described it as a mixture of both squeezing and hitting. She said his ring hurt her.— Sontaya Rose (@SontayaRose) May 3, 2019
The victim testified before lunch she was slapped twice. But now she says she was grasped. She also said she ‘thinks she remembers’ telling someone at school she is afraid of her dad.— Sontaya Rose (@SontayaRose) May 3, 2019
During opening statements on Friday, deputy district attorney Steve Wright said Arambula lost his temper and flew off the handle the night he went into his daughter's room to find she had tossed a toy at her sister.
Defense attorneys say the accuser is very intelligent and went to school the day after the incident with a bruise asking for an ice pack.
RELATED: 'She was really angry that he spanked her' Arambula family explains what led to child abuse charge
"We have video showing that she wants attention. She feels not being listened to and she feels like she's not getting enough attention from her parents," said attorney Margarita Martinez-Baly.
The second-grader took the stand to describe the action she said her father took when he heard her younger sister crying. The girls shared a bedroom at the time of the December incident when she said her father pinned her down and slapped her.
Prosecutors allege the child was coached by her paternal grandmother about what to focus on during police questioning.
Detectives also allege Arambula's wife attempted to sway the child's opinion about the incident.
On Friday, the victim said she thought she remembered her grandmother telling her to talk about the nice things about her dad.
Baly asked jurors to consider the girl's credibility. She also revealed the assemblyman and doctor will be taking the stand in his own defense.
"He's not the perfect father. I don't think anyone is a perfect parent. He did not willfully slap his daughter. He didn't notice the bruise the next day."
Prosecutors also said the evening of the alleged crime wasn't the only time Arambula was heavy-handed.
They said a police investigation also revealed other questionable incidents involving both the 7-year-old victim and her sister, the 6-year-old middle child.
RELATED: Accusations of repeat violence and contradictory statements as trial start for Dr. Joaquin Arambula
Defense attorneys also said the accuser is an avid reader and paralleled her statement to officers to a book she read over Thanksgiving break.
During an interview with Action News in December, Arambula said he spanked his daughter, but she didn't mention that on the stand.
The judge noticed Arambula making facial expressions while his daughter testified. So he cautioned him about these motions and reminded him to refrain from any open expression.
After jurors left for lunch, the judge cautioned Joaquin Arambula about facial expressions and making them while his daughter is testifying.— Sontaya Rose (@SontayaRose) May 3, 2019
Arambula has previously said this case was politically motivated but on Thursday there was no mention of politics playing a part at all.
Legal analyst Tony Capozzi shares some insight into the trial.
"I'm sure people have talked to her what would happen if her dad were convicted. I'm sure she's scared and that tainted her testimony," he said.
Capozzi says the child's credibility will be the crucial element in this case, and it'll be up to the prosecutor to bring in witnesses that can prove her testimony.
Capozzi says it'll ultimately be up to the jury to evaluate the testimony based on the statements she made to police, and the possibility that the child may have been influenced.
There's still a long list of witnesses who will testify, and the trial is expected to start back up on Monday.