contrary to the first two conjuring movies the original Ed and Loraine Warren weren't just folks that investigated Haunted Houses they investigated cases with demonic possession. a case where a man believed he was a werewolf. they investigated a case where a man claimed to be a real vampire. a case of a haunted mirror. a haunted organ. etc

One of their non-haunted house cases was made into a 1983 TV movie, The Demon Murder Case (with Kevin Bacon)
https://www.imdb.com/title/tt0085422/reference

I wouldn't mind seeing a new movie based on that as the TV movie is mediocre.