The Lost Village by Camilla Sten
One day in 1959, the residents of an isolated mining town vanished, taking nothing with them and leaving no trace of where they might have gone. Only a newborn baby and a battered body, tied to a wooden post in the town square and surrounded by stones, remained. Alice Lindstet has spent her entire life hearing her grandmother's stories about the tragedy and is raising funds for a documentary project that she hopes will solve the mystery. She and her film crew have only a few days to explore the village and put together the video they'll need for their fundraising proposals.
The Lost Village is a wonderfully creepy read. The book's description compares it to The Blair Witch Project and Midsommar (which is exactly why I picked it up) but I also saw elements of The Lottery. A few elements are familiar, but if the film crew wasn't isolated, they'd just walk away as soon as they realize that something is wrong. The plot alternates between what is happening with Alice and her friends in the present and the events leading up to the disappearance in 1959. It's suspenseful and sad and kept me turning pages until the end.