User blog comment:Creepysss/Sinister: True or False?/@comment-25052433-20140902195901

You have to understand that 'Based on a true story' is a very loose term used in movies to get viewers to buy tickets. There could have been a report of a child claiming to see something in a picture, and that would be enough for the movie producers to tag on 'based on a true story.'

So, to answer your question, no, Sinister is not a true event, nor is any of the footage legit.