That's really not good enough though. If it's factual writing it should be the articulatedly-recounted facts, with any speculation clearly marked as such.
Otherwise we're into Creepy Pasta territory, or
yarns.
This can be done intelligently and is how certain true crime writers work.
Edited to add that I personally wouldn't waste any time on Tom Slemen or any other author I've found to be
elaborating or downright
fabricating his research.
Lying is lying, with writers and readers as in any other relationship. We need to know what's true and what's not.
We accept actual storytelling because we can tell which part is the truth, where human interactions are interestingly described both working and going wrong. The
yarn is just padding.