Their town was washed away by a hurricane and the people drowned. They left Roanoke Island and went to live with the Natives. They left Roanoke Island and went to live in some other place. Let's look at each possibility. When John White got back to Roanoke Island in 1590 he did not find any bones or bodies or any signs of fighting.
Bones last a long time.
If the Natives had killed the colonists, there would probably have been some remains or other signs of violence. We can guess that the colonists were not killed on Roanoke Island. When the English first came to Verginia they brought with them diseases, such as flu and smallpox, that were new to the Indians. They had no immunity against them and many died very quickly. Letters written by the colonists tell us that the English remained healthy.