A Miami-Dade man has pleaded guilty to the horrific murders of his wife and her two young daughters nearly 14 years ago and will now face a possible death sentence.

Alberto Sierra, 42, pleaded guilty on Friday to three counts of first-degree murder, three counts of kidnapping, two counts of abusing a human body and one count of armed burglary.

The charges stem from the killing of Gladys Machado and her 4- and 6-year-old daughters, who were found slain in a northwest Miami-Dade home on Nov. 13, 2012.

Authorities said days earlier, Sierra, Machado and the girls were at the Mall of the Americas when the couple got into an argument and he pulled out a knife then drove them to the home.

Sierra locked the girls in one room and locked himself and Machado in another room, authorities said.

According to an arrest affidavit, Sierra suffocated Machado with a plastic bag “and subsequently sexually assaulted her,” then let one of the girls out of her bedroom and suffocated her.

He suffocated the other daughter with a plastic bag while she slept, then sexually assaulted the other daughter, the affidavit said.

The bodies of Machado and her daughters were found three days later in a closet at the home, police said.

Sierra and Machado were married but had no children in common and were not living together when the murders took place, the affidavit said.

Authorities had questioned and released Sierra but he later gave a full confession to the murders, the affidavit said.

Sierra will now face a punishment phase where a jury will recommend whether he should get life in prison or the death sentence.

Jury selection was expected to begin Aug. 17.