A jail call — and doubt about plea — emerges before killer’s death penalty trial

Crime admin September 10, 2026 0 Comments

A jail call — and doubt about plea — emerges before killer’s death penalty trial

In the throes of jury selection, prosecutors cast doubt on the validity of Alberto Sierra’s guilty plea, pointing to a jail call where the convicted killer said his attorneys had an agreement that would spare him from the death penalty.

But when asked about the comments he made during the call, Sierra, 42, told Miami-Dade Circuit Court Judge Marisa Tinkler Mendez he was having a conversation with a friend — and wanted to “alleviate” his friend’s concerns about him being executed.

Tinkler Mendez asked Sierra, who was put under oath, if his attorneys promised him a certain outcome or told him there was an agreement to get him a life sentence.

“No ma’am,” Sierra responded as he stood before the judge.

READ MORE: He killed his wife and her two young girls. Jury will decide if he gets to live

On Aug. 7, Sierra pleaded guilty days before his trial was to begin. He was charged with three counts of first-degree murder and kidnapping, two counts of abuse of a human body and one count of burglary.

His plea was not the result of a deal with prosecutors, meaning he would go straight into a sentencing trial where jurors will be tasked with deciding whether Sierra should be condemned to Florida’s Death Row or sentenced to life in prison.

Through his plea, Sierra admitted to suffocating his estranged wife, Gladys Machado, 29, and her daughters Julia Padron, 7, and Daniela Padron, 4, with a plastic bag on Nov. 10, 2012. The bodies of Machado and her two daughters were found three days later inside a bedroom closet in their Flagami home in the 7300 block of Northwest Fourth Street.

Upon hearing about Sierra’s comments, the judge said she wanted to hear directly from Sierra due to her concerns about his change of plea. Tinkler Mendez said the matter needed to be addressed urgently as she and the attorneys on the case had already screened 800 jurors.

During the hearing, the judge also asked Sierra’s attorneys if they made any promises or representations that could lead Sierra to believe there was an agreement to spare him from execution.

Attorneys Joyce Brenner, Khurrum Wahid and Carmen Vizacaino all assured the judge that they did not.

What did Sierra say in the jail call?

The Miami Herald obtained a copy of Sierra’s jail call — and a transcript produced by the Miami-Dade State Attorney’s Office — in a public records request on Thursday afternoon.

In the Aug. 7 phone call, which is in Spanish, Sierra is heard talking to a friend. He told the man he pleaded guilty earlier that day, and his friend asked him if he can still be sent to Death Row.

“I thought that if you pleaded guilty, you wouldn’t go to death, you’d go to life,” Sierra’s friend said.

“My attorney and the judge, the agreement they had was that,” Sierra said. He told the man that the judge will have the final say on his sentence. In Florida, judges can override a jury’s recommendation if jurors say the defendant should be sent to Death Row.

Later during the call, Sierra said he felt like he was “sold out” — and appeared to regret pleading guilty.

“I shouldn’t have done it,” Sierra said. “I don’t think I made the right decision.”

But Sierra then said that he would have been worse off had he not pleaded guilty, and that he wants to get to “the other side” to hug his mother and have her visit him.

During the call, Sierra also discussed media coverage of his case, saying he felt everything was “arranged” because news cameras were present when he entered his guilty plea. His friend also read him snippets of a Miami Herald news article and told him he was browsing through the news.

This story was originally published September 10, 2026 at 4:58 PM.