More than five years after the World Trade Center came crashing down, human remains keep cropping up near the site, angering family members who lost loved ones in the terrorist attack.

WTC Families for Proper Burial say the discovery of the bones on the northern edge of the site is another reminder that city and state authorities need to systematically comb the area.

"We can no longer rely on accidental discoveries," the group said in a statement. "This must be a deliberate search. May this awful news be the catalyst needed to go back and do the job well."

A Consolidated Edison crew doing excavation of a manhole at street level found the remains, some as big as arm or leg bones, said Steve Coleman, a spokesman for the Port Authority of New York and New Jersey, which owns the trade center site.

The location where the bones were found is next to where a podium is erected on Sept. 11 anniversaries for families to read the names of their loved ones.

Con Edison said that at the direction of the Port Authority it entered the lower Manhattan site on Wednesday to remove material from two manholes that had been damaged and abandoned after the 2001 collapse of the twin towers.

Crews hauled the excavated materials Wednesday to a work center more than a mile away, in the Chelsea neighborhood, as is customary, Con Edison said. No one noticed there were human remains.

On Thursday morning, a contractor working for the Port Authority noticed the remains, Con Edison spokesman Chris Olert said, and the medical examiner's office was contacted.

The area was roped off, and investigators sifted through dirt under a white tarp. The team of workers included forensic anthropologists who are overseeing the medical examiner's massive effort to identify Sept. 11 trade center victims.

Police said there was no evidence of wrongdoing, and an investigation was to continue Friday, the same day WTC Families for Proper Burial planned to hold a news conference in Manhattan "to express our outrage at the continued cavalier attitude toward the retrieval of human remains."

Con Edison said is "shares the great sensitivity felt by families and rescuers associated with the tragedy" because many of its employees have been personally involved in the restoration and recovery efforts.

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.

The remains of Charles Wolf's wife, Katherine, 40, were never recovered. He said his wife, an employee of insurer Marsh & McLennan, perished on the 97th floor of the north tower.

"I am totally shocked that this was found in the pit," said Wolf, who showed up at the Chelsea Con Edison site after being contacted by television stations. "The fact that they were found in ground zero says there was some major, major shortfall in the recovery effort."

Wolf, 52, of Manhattan, said a "qualified independent party," such as investigators with the military's Joint POW/MIA Accounting Command, or JPAC, which looks for American soldiers who go missing, should handle the Sept. 11 remains search.

"We've got a problem right now," Wolf said. "Where else are we going to find them next?"

During the 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 DNA in thousands of those pieces, many small enough to slip into a test tube, was too damaged by heat, humidity and time to yield matches in the many tests forensic scientists have tried over the years.

The city told victims' families last year that it was putting the project on hold, possibly for years, until new DNA technology was developed. Every known process had been tried.

But last month, Medical Examiner Charles Hirsch said that advances had been made by Bode Technology Group, the Virginia company contracted to work on recovered Sept. 11 bone fragments, and that "new identifications will be forthcoming."

A medical examiner's office spokeswoman, Ellen Borakove, said Thursday that no new IDs had been made but they still were expected.

Besides the new remains found by the utility workers, the lab also has recently received hundreds of bone fragments discovered on the roof of a building just south of where the trade center stood. The building had been condemned since the attacks and was about to be torn down when workers found the bone pieces.