As The Lost Colony of Roanoke becomes more rooted in history, its mystery slowly unfurls because of still emerging evidence and advanced technology. Still, discovering what happened to the two colonies totaling more than a hundred early British settlers will require either more clues, technology not yet invented, or both.

Brent Lane from the First Colony Foundation, dedicated to solving the Roanoke disappearance, uncovered one new piece to the puzzle in May of 2012: a map leading towards a planned fort about 50 miles inland of the original Roanoke settlement (off the coast of what is now North Carolina). The map had been discovered long time ago, but only recently did Lane notice its maker obscured the location of the fort with a series of patches, National Geographic reported.

"Our best idea is that parts of Raleigh's exploration in North America were a state secret, and the map 'cover-up' was an effort to keep information from the public and from foreign agents," said Eric Klingelhofer of Mercer University in Macon, Georgia.

The discovery of the map added depth to previous theories centered on a crisis -- whether it be disease, attacks from Indians, or attacks from the Spanish -- and evacuation, and sparked exploration of a less common theory proposed by Klingelhofer, according to Nat Geo: that colonists migrated to a small Native American settlement known as Mettaquem rather than the island of Croatoan, which matched the farewell notes carved on the tree.

The existence of the map means the settlers had some sort of contingency plan in place should things go awry, which they evidently did. Some researchers believe one aspect of that plan was to split into groups ("a good strategy," according to Klingelhofer), which potentially led each group to a different fate. Maybe some did go to Croatoan, while some went to Mettaquem, others were killed by natives and the Spanish, and the remainders assimilated within Native American tribes. Maybe there is no one answer.

To test his Mettaquem theory, Klingelhofer used ground penetrating radar (GPR) and searched the ground for colonist structures, according to Nat Geo. He and fellow researchers detected a few groups of wood that could have been a shelter and a fence, indicating some group of people once settled there (though the structures could belong to groups as late as the 1700s; the Roanoke Colony was last seen in 1590).

Even if the case remains forever cold, members of the First Colony Foundatoin won't have started their group in vain. "I've always said I'd be just as happy if it was never solved. I like it being a mystery," said North Carolina attorney Phil Evans, who helped start the Foundation.