Snowbound Mystery (The Boxcar Children Book #13) Vintage Paperback by Chandler Warner 1990

One warm night four children stood in front of a bakery. No one knew them. No one knew where they came from. Henry, Jessie, Violet and Benny used to live alone in a boxcar. Now they have a home with their grandfather and are spending a week in a log cabin in the woods. When a terrible snowstorm hits the area, the Boxcar Children are trapped!

To make matters worse, there's something very suspicious about their cabin, What are all the strange markings on the closet door? And what are all those strange noises the Boxcar Children hear in the night...?