Conversation so far:
Was Henry Hill an informant?
In 1980, Henry Hill was arrested on narcotics charges and became an FBI informant.
What did Henry Hill testify about?
Henry Hill testified against his former mafia associates, resulting in 50 convictions, including those of caporegime Paul Vario and James Burke on multiple charges.
Was Henry Hill afraid of testifying?
Is there any important information about the article that you found significant about Henry Hills informancy?
Hill, his wife Karen, and their two children entered the U.S. Marshals' Witness Protection Program in 1980, changed their names

Question: how long was they in the Witness Protection Program?
Self-contained rewrite: How long was Henry Hill and his family in the Witness Protection Program?