score:18
Here's what evidence they had:
Because there was no cross, John White took this to mean they had moved to "Croatoan Island" (a.k.a. Hatteras Island).
Also, Thomas Harriot, an employee of Raleigh, worked with White to explore the area of Roanoke and plan out the voyage. Harriot wrote about the fauna/flora in his report A Brief and True Report of the New Found Land of Virginia. But what is most important about that report is that he wrote about the native Americans in the Roanoke area. He wrote that the relations between the Roanoke Indians and the English settlers were mutually calm.
That is all that is known. It is still a big mystery.