The remains of a man killed at the World Trade Center on September 11th have been positively identified more than 15 years after the attack, the city medical examiner announced Monday.

The man, whose name is being withheld at his family's request, is the first victim of the tragedy to be identified since March 2015. According to Dr. Barbara Sampson, the city's chief medical examiner, the identification was a direct result of recent improvements in the DNA testing process.

"This is the natural outgrowth of always making improvements and retesting the remains," Sampson told the Post. While previous tests had failed to identify the man, the medical examiner credited more sensitive technology and an advanced bone extraction method with helping to make a positive match. Both those improvements were deployed by the medical office at the start of this year, according to the Times.

Around 40 percent of the 2,753 people who died in the attack have yet to be identified—or 1,112 individuals.

Currently, the medical examiner's office is working with more than 20,000 pieces of remains, from which they remove DNA through a bone extraction process. Once obtained from the bone fragments, the DNA is compared with genetic material donated to the lab by the family members of victims.

Those remains are stored in an underground repository beside the National September 11 Memorial & Museum, according to the Times, while the testing is done at a DNA lab in Kips Bay.

"Since the immediate days following the World Trade Center disaster in 2001, the Office of Chief Medical Examiner has worked to identify the victims, and we will continue to uphold this commitment using the most advanced scientific methods available," Sampson added.