The jury that must recommend whether Alberto Sierra spends the rest of his life in prison or receives the death penalty listened on Monday to a VHS recording in which the accused, with a measured voice and a practically indifferent tone, describes how he ended the life of his estranged wife and their two young daughters in November 2012, in one of the most shocking crimes recorded in Miami-Dade in recent decades.
The session took place within the context of the sentencing phase of the trial, with Sierra seated in the courtroom showing no emotion as the 12 jurors listened to the statement he gave to the detectives on November 19, 2012, nine days after the murders and six days after the bodies were discovered.
The recording allowed for the reconstruction, using Sierra's own words, of the sequence that began with a jealousy argument and ended with Gladys Machado and her daughters Julia and Daniela Padrino suffocated with plastic bags.
A jealousy-fueled argument that ended in a triple murder
According to the testimony presented to the jury, Sierra and Machado, who were separated, had taken the girls to the Mall of the Americas, where they bought them ice cream.
In the parking lot, Machado received several calls from a man and rejected them. Sierra, who suspected that his wife was being unfaithful, reacted with jealousy and tried to find out who was calling her.
"I was furious," he admitted during the interrogation.
Sierra explained that he wanted to obtain Machado's phone password because he was looking for evidence of an alleged infidelity. The argument escalated, and the two ended up struggling over a knife, according to the reconstruction presented during the trial.
The prosecutors maintain that, after taking control of the weapon, Sierra forced Machado and the two girls to move under threat to the home where the couple had previously lived, located in block 7300 on Northwest Fourth Street, in the Flagami neighborhood.
Once there, he locked the girls in a room while he continued arguing with Machado to get the password to his phone.
The woman's refusal led to even greater violence. Sierra tied her wrists behind her back with a white nylon rope and stabbed her with a knife while continuing to demand the code for the device, as stated during the hearing.
"I tied his hands behind his back."
In the recording, Detective Juan Carlos Chaidez from the Miami-Dade Sheriff's Office asked Sierra if he knew he was being held for the murders of Gladys, Julia, and Daniela.
"Yes," Sierra replied. "I tied his hands behind his back."
In response to the investigator's questions, he explained that he had used a white nylon rope to immobilize Machado's wrists.
He later recounted that he took a yellow plastic bag from the Sedano's supermarket chain and covered the woman's face with it to suffocate her.
The statement reproduced in court added another detail about Machado's final moments: the woman tried to resist while Sierra held the bag over her face.
“She was moving and fighting,” was heard during the reconstruction of the interrogation.
Sierra later stated that he cried for what he had done.
Julia saw her dead mother
The violence did not end with Machado. Sierra described to the detectives how he later killed the two daughters of the woman, Julia Padrino, aged six, and Daniela Padrino, aged three.
Julia had seen what had happened with her mother.
"He saw that his mother was dead and started to cry and scream. I grabbed the Sedano's bag and put it over his face," Sierra recounted.
He then went over to Daniela, who was sleeping.
"I went to the girls' room, Daniela was sleeping, I sat on top of her and did the same," he stated.
According to his confession, he used the same method to end the lives of the three victims and subsequently placed their bodies in the closet of the master bedroom.
At the end of describing that sequence, Sierra stated: “I don’t know, I went crazy.”
Abuse of corpses and an attempt to erase evidence
The statement heard by the jurors also addressed what happened after the murders.
The Prosecutor's Office claims that Sierra sexually abused the corpses of Machado and Julia. The prosecutors also allege that he disfigured Machado's face with a knife.
During the opening arguments of the sentencing phase, the lead prosecutor, Abbe Rifkin, stated that Sierra made cuts to Machado's face so that she would never again be beautiful for another man.
Sierra also described to the investigators his attempts to eliminate evidence from inside the house. In response to a question from Chaidez about which areas he had scrubbed, he listed the master bedroom, the walk-in closet, the bathroom, the kitchen, the living room, and other areas of the house.
The three corpses remained inside the master bedroom closet until a neighbor, alerted by the strong smell of decomposition coming from the house, made the macabre discovery on November 13, 2012.
DNA changed the interrogation
Detective Chaidez stated before the jury that Sierra did not initially disclose what had occurred and provided false information to the investigators.
The situation changed when he was confronted with the DNA evidence found on the victims.
Chaidez recalled that the defendant's physical reaction was immediate.
"He intertwined his fingers, looked at the table for several seconds, and began to tremble or shudder. It was then that he said something like he was going to tell us what had happened," stated the detective.
Prosecutor Rifkin used that moment during the interrogation to highlight to the jurors that the confession occurred after Sierra was confronted with the evidence.
The defense questions the interrogation and claims a brain injury
During cross-examination, defense attorney Joyce Brenner asked Chaidez about the deliberately calm tone he maintained during the interview and whether that strategy aimed to establish a rapport with Sierra to encourage him to speak.
Chaidez responded that he had already established a relationship with the defendant during previous meetings, but he noted that something in his behavior had caught his attention from the very beginning.
According to the explanation, Sierra appeared excessively calm when discussing Machado's alleged infidelity and extramarital relationships, a reaction that the detective found strange given the circumstances.
The defense strategy, however, goes far beyond questioning the police interview. Sierra's lawyers are trying to convince the jury that there are sufficient mitigating circumstances to avoid the death penalty.
One of their main arguments is a severe traumatic brain injury that Sierra is said to have suffered during his childhood after being hit by a car. According to the defense, the accident fractured his skull and caused him to lose part of the frontal lobe, subsequently affecting his personality and cognitive functioning.
The jury will decide between life imprisonment and the death penalty
Sierra, a 42-year-old Cuban, pleaded guilty in August before Judge Marisa Tinkler Méndez to nine charges: three counts of first-degree murder, three counts of kidnapping, two counts of corpse abuse, and one count of armed burglary. He did so without reaching any agreement with the prosecution.
When the judge reminded him that he was facing the death penalty, he responded, "Yes, ma'am. It's been 14 years, so..."
The phase currently underway does not seek to determine his guilt, which Sierra has already admitted, but rather to establish the punishment. The 12 jurors must recommend life imprisonment or the death penalty.
Under the reformed Florida law of 2023, unanimity is not required to recommend the death penalty: it is sufficient for at least eight of the 12 jurors to vote in favor.
The chief prosecutor, Abbe Rifkin, has described the murders as "especially heinous, atrocious, and cruel," while the defense hopes to use the brain injury and other aspects of Sierra's personal history as mitigating circumstances to request that he spend the rest of his life in prison.
According to data from the Death Penalty Information Center cited in July 2026, there are currently five Cubans sentenced to death in Florida. If the jury
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