Hidden in the Haunted School: The Boxcar Children Mysteries, Book 144

The old abandoned school in Silver City is being fixed up as an art center and the Boxcar Children volunteer to help clean up the place. But the other volunteers are scared by the spooky goings-on in the schoolamp;mdash;doors lock by themselves, and chalkboard messages appear out of nowhere! Will the Aldens find out the secret of the haunted school?