Investigators have collected evidence that may yield DNA in the case.

A bone sample the size of a thumb can yield mitochondrial DNA to link a man missing 60 years to a child in short pants.

As a result, the rare samples were subjected to whole genome amplification (WGA), which yielded enough DNA for 200 or more reactions.

Preserved organs, tissues and fluids in the bodies could yield unfragmented DNA for genetic studies, as well as insights into Inca health and nutrition.

However, the 500-year-old subfossil bones yielded different DNA.

The nuclei we've tested so far have yielded promising DNA, though of course we have yet to reach the sexual organs.

"We're realistic that not all the remains are going to yield DNA," said John Cartier, who lost his brother, James, on Sept. 11.

Hair can also yield DNA, if they get a root, or they can simply match hair at the scene to hair on your head.

Anything that can yield DNA has been sent in: shirts, gloves, towels, even brain tissue from the grill of a car.

But Mr. Masters acknowledged that the envelope may not yield enough DNA to conduct the sophisticated tests.