'We never recovered him': Quest to identify remains from Ground Zero continues

For 25 years, the only physical trace Juliette Scauso has had from the last day of her father's life is his mangled firefighter helmet.

Scauso's father, Dennis - part of a New York City Fire Department (FDNY) hazmat unit for 12 years - initially was not scheduled to work on 11 September, 2001, but switched shifts for the overtime pay.

The Long Island father of four was likely in the South Tower of the World Trade Center when it collapsed, the Scauso family was told. The helmet with his badge number was found months later.

"I've spent essentially my entire life knowing my father died, and learning to live with the fact that we never recovered him," said Scauso, who was four when he died.

Dennis Scauso is one of more than 1,000 people killed on September 11 in New York who have yet to be identified, according to New York City's Office of Chief Medical Examiner. Nearly 3,000 people died in the World Trade Center attacks that day.

Last month, the city announced the identity of a previously unknown victim of the terrorist attacks - the 1,654th person - using a new technology called forensic investigative genetic genealogy - or FIGG.

"There is real promise in using this approach," said Angela Soler, director of forensic anthropology in the city's medical examiner office. "There's hope for more families to receive answers, and hopefully we'll be able to test more remains in the future using this technology as well."

Since 9/11, Soler's office has sought to identify the remains of the 2,753 victims who died in the World Trade Center. So far, 60 percent of those killed have been identified.