James Wan to fast-forward to the ’80s for the next Conjuring movie

Now that big-budget mashups of I Love The ’80s are all the rage, James Wan—a director who knows a hit franchise (or low-hanging fruit, for that matter) when he sees it—plans to do the same for the next Conjuring movie. Speaking to IGN, the director says he’s already got the next paranormal case for supernatural super-agents Ed and Lorraine Warren picked out, but he’s not saying which one. He does give this hint: “[The Conjuring and The Conjuring 2] are both set in the ’70s, I think Conjuring 3 has got to be set in the ’80s.”
That does narrow things down a bit. Both of the Conjuring movies released so far were based on actual cases from the Warrens’ files, so it stands to reason that the third one will be, too. So, which hauntings did Ed and Lorraine Warren investigate in the ‘80s? To Wikipedia!:
First, there’s the case of Arne Johnson, who attempted to plead not guilty by reason of demonic possession in his trial for the killing of his landlord in 1981. The Warrens were involved in the case beginning several months earlier, where they exorcised Johnson’s fiancee’s younger brother of a supposed demon. During the ritual, the demon purportedly left 11-year-old David Glatzel’s body and jumped into Johnson’s, and forced the man to kill his landlord months later: