LOS ANGELES (KABC) -- The penalty phase began Monday for the Palmdale man found guilty of murdering his girlfriend's 8-year-old son, Gabriel Fernandez.
During opening statements, prosecutor Scott Yang and defense attorney Michael Sklar made their cases for and against giving Isauro Aguirre the death penalty.
Yang showed the jury very graphic photos of Gabriel's injuries, including in his mouth and genitals. Many in the courtroom became very emotional, shedding tears or sometimes having to exit the room.
"The only reasonable, just and appropriate penalty this defendant should receive is nothing less than death," Yang said.
Palmdale abuse case: Isauro Aguirre found guilty of 1st-degree murder
Sklar said that while he disagrees with the verdict of first-degree murder, he respects the jury's decision.
He told the jury he will be asking them to sentence Aguirre to life in prison, so he will wake up every morning in a prison cell thinking about the horrific actions he committed to Gabriel and his family.
Sklar also said that during the penalty phase, he plans to present mitigating factors in order to show who Isauro was before he met Pearl Fernandez, Gabriel's mother.
He described Aguirre as gentle, kind and exhibiting tremendous patience while working with the elderly prior to meeting Pearl Fernandez, who is also charged with murder and will be tried separately.
They also said he was mentally slow, easily manipulated and had no history of violence until he moved in with Pearl.
"He is not that person now and he's not that person before Pearl," Sklar said, asking the jury to look not just at the crime he committed, but his entire life - his entire 37 years here on earth.
Following opening statements, multiple witnesses testified.
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Gabriel's cousin, Emily Carranza, described the boy as a "normal kid" who played outside with his cousins, behaved well and liked being around his grandmother Sandra and uncle Michael.
Carranza created the Facebook page, Gabriel's Justice. She said it was initially just a GoFundMe account set up to pay for funeral expenses, but it developed into something bigger to bring awareness to child abuse.
"Gabriel's case is not the only one," she said.
Also taking the stand were firefighter-paramedics Sean Fox and Robert Metro. Both responded to Gabriel's Palmdale apartment on May 22 - the day the boy died.
When shown graphic photos of Gabriel's injuries, Fox said he has never seen such injuries on a child caused by an adult. At this point, Gabriel's biological father stormed out of the courtroom, returning later carrying tissues.
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Fox said when he arrived at the apartment, Aguirre showed no emotion.
"I'd describe the emotion like 'what did I do' type of thing," Fox testified. "Aguirre showed no empathy or sympathy at the scene."
Metro also commented on Aguirre's demeanor at the scene - specifically the way Aguirre was holding Gabriel.
"Just the way he (Gabriel) was being held caught me off guard," Metro told the jury. He said Aguirre was holding Gabriel like he didn't want anything to do with him.
When asked by Yang if Aguirre was holding Gabriel in a caring way, Metro replied, "No, he was holding him like he was dirty."
"It was a strange scenario, in that you wanted to save him," Metro said. "But on the same token, the amount of trauma you had seen...you almost wanted him to be free of it. When he passed, I felt almost relief for him."
Metro said he could never forget Gabriel, even if he wanted to.
"This will stick with me forever," he said. "I relive it every day."
Palmdale abuse case: Attorneys make cases for, against death penalty