Ten bone fragments discovered on the rooftop of a skyscraper near the World Trade Center site more than four years after the attacks are human, officials said Friday. The pieces of bone, ranging in size from half an inch to two inches (1-5 centimeters), were found on three days last month by construction workers sifting through gravel on top of the former Deutsche Bank building, officials said. Test results returned last week indicated the fragments were human, said Ellen Borakove, a spokeswoman for the medical examiner's office. She said it was too soon too tell whether the remains came from one person or more than one. The city medical examiner will try to identify the remains by extracting DNA and checking it against a database of World Trade Center victims, said Borakove. "We're hoping to be able to create some profiles," she said.