Certainly one of the better modern efforts imho.
21 Days (2014, Kathleen Behun)
3 clods ignore
several red flags whilst setting up to debunk an "urban myth"
The good old Native American burial ground as back story .... aww does your heart proud ... the old ones are the best ETC
So guess how long they're staying ...
go on guess 
Decent enough build up with the gradual eerieness, though the ending is a tad fraught visually (not as much as
The Taking Of Deborah Logan, which still takes the prize in the WTF IS GOING ON stakes ahem).
I'd write more but I'm just going to investigate these weird noises outside ....