This is book number 42 in the The Boxcar Children Mysteries series.
When the Aldens hear that Mr. Wood’s cat, Spotzie, is missing, they immediately help out by putting up LOST CAT posters and going door-to-door with a photograph of the cat. But along the way they meet some strange characters, receive frightening phone calls, and even find a cat that looks just like Spotzie — but is it? It seems that the more they search, the more mysterious the mystery becomes!
The Boxcar Children Series was created by Gertrude Chandler Warner, a teacher, when she realized that there were few, if any, books for children that were both easy and fun to read. She drew on her own experiences in writing the mysteries. As a child, she had spent hours watching trains near her home, and often dreamed about what it would be like to live in a caboose or freight car. In each story, she chose a special setting and introduced unpredictable, unusual or eccentric characters, to help highlight the Aldens’ independence and resourcefulness. Miss Warner lived in Putnam, Massachusetts until her death in 1979.