No criminal charges will be filed after four newborn babies found frozen and in shoe boxes wrapped in tin foil inside a freezer in a Boston apartment, officials have determined.

Suffolk District Attorney Kevin Hayden released the final investigative report on the case earlier this week.

The babies were found in 2022 in a freezer in a south Boston apparent owned by Alexis Aldamir. A man called the police after making the gruesome discovery while cleaning out his sister's apartment.

Two of the babies were male and two were female. Investigators determined they were all full-term with their umbilical cords still attached. DNA tests revealed the babies were full siblings.

The autopsy found no signs of internal or external trauma and no evidence of obvious injuries. There were no signs of food, or milk, or formula inside the babies' stomachs.

The medical examiner found the cause of death for all the babies to be "undetermined," and could not definitively determine whether the babies had been born alive.

Aldamir, 69, purchased the South Boston apartment in October 1983. Investigators tracked her to a residential healthcare facility. Based on a DNA sample she is the mother of all four babies.

But when questioned about the babies, Aldamir appeared confused and demonstrated a lack of understanding about where she was and who she was speaking to, officials said, though she had once worked in a Boston accounting firm. 

The biological father of the babies was also identified, but he died in 2011.Investigators also determined that Aldamir gave birth to a baby girl in April 1982. The birth certificate listed Alexis Aldamir as the mother but did not include the father's name.

The two had a fifth child that was given up for adoption, said officials. 

In explaining why no charges were being filed in the case, Hayden said there needed to be evidence that the victims were alive before their deaths, and a cause of death determined by the medical examiner. The autopsy found no signs of internal or external trauma to the babies and no evidence of obvious injuries, he noted.

Aldamir also appeared to be incapable of withstanding or understanding a trial.

Officials cannot "ethically move forward with a case that, in good faith, it believes it cannot bring to trial," said a statement from the prosecutor's office.

Hayden called the investigation "one of the most complex, unusual and perplexing that this office has ever encountered." It's "now complete," he said. "While we have some answers, there are many elements of this case that will likely never be answered," Hayden added. 

"We will never know exactly where or when the four babies found in Alexis Aldamir's apartment were born.  We will never know if the four babies were born alive, and we will never know exactly what happened to them.  We will never know how Alexis Aldamir concealed her pregnancies, or why she chose to do so," he said.