Yes, it claims to be based on true events, but some elements might be dramatized for cinematic effect.
It purports to be true, but as with many such movies, there's likely a degree of fictionalization to make it more engaging and scary. The core inspiration might come from real-life occurrences, but the details could be embellished.
Supposedly it is. However, in the world of horror movies, even when based on true stories, they often take liberties to amp up the thrills and chills. So, while it has a true story foundation, don't expect a 100% accurate account.