NEW YORK (AP) – There is new hope for the families of hundreds of Sept. 11 victims whose remains were never identified, according to the city medical examiner, who sent letters on Thursday notifying them that “new identifications will be forthcoming.”

Medical Examiner Charles Hirsch wrote to victims’ relatives and said advances made by Bode Technology Group, the Virginia company contracted to work on recovered Sept. 11 bone fragments, “have provided us the opportunity to renew our efforts to identify your loved ones.”

Five years after 2,749 people died in the World Trade Center attack, families of about 1,150 victims still have not received word that their loved ones’ remains were found amid the rubble. During the arduous excavation of the 110-story twin towers, which began the evening of the attacks and lasted for nine months, about 20,000 pieces of human remains were found.

The city told families last year that they had exhausted all available DNA technology and were putting the project on pause until new processes were developed.

But on Thursday, the medical examiner said his office was “working actively on World Trade Center identifications, and new identifications will be forthcoming.”

“I cannot predict how many or the time it will take,” Hirsch said. “My colleagues and I reiterate our commitment to you: We will never quit.”

Bode’s lead forensic scientist on the project, Ed Huffine, told The Associated Press that the new process has a high success rate.

“What we have done over the last year is to improve the amount of DNA we recover with each sample,” Huffine said in a telephone interview. “It’s a much purer DNA extract. It’s much easier to work with.”

He said the lab already has sent DNA profiles back to the medical examiner’s office to be matched. In the weeks after the terrorist attack, the city asked families for victims’ personal effects, such as toothbrushes and combs, so it could collect DNA samples, and it created profiles that could be compared with what was extracted from the recovered remains.

Medical examiner’s office spokeswoman Ellen Borakove said no new matches have been made but the technology is so encouraging that Hirsch wanted to notify the families that identifications are likely.