The Vandermist Dossier

From BoardGameGeek:

In the spring of 1979 Abigail Vandermist, 19 years old, discovers people mysteriously disappearing from the village of Oostzoom. She starts her investigation. Her sister Helena stays behind in Amsterdam...until she notices not hearing anything from Abby for weeks. In The Vandermist Dossier, you are being asked to help in this cold case. You receive the file by post and then you can start digging in the information. Spend an evening working to solve puzzles, unlock hidden clues, and unravel the mystery of the Vandermist family. Will you and your guests be able to solve the mystery and discover what happened? Note that in the original Dutch production of this escape-room game, the missing girl is Abigail Boekanier, thus the name of the game is Het Boekanier Dossier.