Jurors hear Miami man's taped confession to murders of wife, 2 girls in trial: "I don't know, I went crazy"

Jurors in the trial of a 42-year-old man accused of killing his estranged wife and her two young daughters heard his taped confession and saw video of the girls dancing, while he showed no visible emotion in court.

Alberto Sierra is on trial in the November 2012 deaths of Gladys Machado, 29, and her daughters, Julia Padrino, 6, and Daniela Padrino, 3.

In the 2012 confession tape played for the jury, Sierra told detectives he killed them.

"I don't know, I went crazy," Sierra said on the tape.

Lead Detective Juan Chaidez testified that Sierra confessed days after the deaths, after being confronted with DNA evidence linking him to the crime scene, including DNA found on Julia's clothing.

According to investigators, Sierra held Machado at knifepoint in her car on Nov. 10, 2012, after an argument over a call on her phone. They say he forced Machado and her daughters into her home, tied Machado's hands behind her back, and suffocated her with a plastic bag.

Investigators say Sierra confessed to pacing around the bedroom for about an hour before sexually abusing Machado's body, then using the same bag to suffocate her daughters. He then tried to clean up the scene and discard Machado's belongings, they say.

After the confession tape was played, defense attorneys cross-examined Chaidez.

More witnesses are expected to testify Tuesday, including Machado's son, Michael Padrino, who was staying with his great-grandmother on the day of the killings.