The remains have been subjected to a battery of tests, including DNA, carbon dating and environmental analysis in an effort to confirm the identification.
Dr Attila Nyikos, of the NDGDM, told the BBC News website that a police investigation had been opened and tests were still being carried out to determine the environmental impact of the leak.
The dispersant that has been used in the largest amounts on this spill, Corexit 9500, is among the most toxic to certain organisms of all those approved by the Environmental Protection Agency for use in oil spills, according to EPA tests.