By Mark Hosenball WASHINGTON (Reuters) - The FBI has warned that followers of the QAnon conspiracy theory could again engage in violence against political opponents out of frustration that the theory's predictions have not come true. Believers in the conspiracy theory - which casts former President Donald Trump as a savior figure and elite Democrats as a cabal of Satanist pedophiles and cannibals - played a prominent role in the deadly January 6 assault on the Capitol. In a June 4 bulletin distributed to members of Congress and seen by Reuters, the FBI said its experts believe that some believers...