Twenty-five years after the September 11, 2001, terrorist attacks, approximately 1,100 families of victims still await identification of the remains of their loved ones, according to a former death investigator.

Barbara Butcher, who worked for 23 years at the New York City Medical Examiner's Office, including at Ground Zero, described the painstaking process of identifying victims from minuscule bone fragments found on rooftops and debris. She noted that while advanced DNA testing has helped, a significant portion of the nearly 3,000 victims killed in the attacks remain unidentified.

Of the 2,753 people who died at the World Trade Center, Butcher stated that only 60 percent of the remains have been identified. The remaining 40 percent, totaling around 1,100 individuals, have not been identified, leaving their families without a body to bury.

Butcher recounted the immense devastation and scale of destruction at Ground Zero, which she found inconceivable at the time. She was tasked with overseeing the identification process, which involved meticulous tagging, examination by medical examiners and forensic anthropologists, and extensive DNA testing on even the smallest fragments.

Investigators collected data, including specifics like the length of a loved one's toe, to aid in identification. The process was described as overwhelming yet miraculous as technology advanced, allowing for retesting of remains with improved DNA extraction capabilities.

Al Qaeda terrorists hijacked four planes on September 11, 2001, crashing two into the Twin Towers, one into the Pentagon, and the fourth in a field in Pennsylvania after passengers and crew fought back. The attacks remain the deadliest terrorist incident in U.S. history. Butcher emphasized that all deaths resulting from the attacks were homicides, caused by the terrorists. She recalled the psychological toll on her colleagues who worked tirelessly at the recovery site, as well as the subsequent health issues they faced.

Of the 2,753 people who were killed in the Twin Towers, Butcher said that only 60 percent have had their remains identified