Kinda sorta The Painted Bird.

The Painted Bird was published and marketed as a fictional work although it was generally assumed that it was based on the author's experiences during World War II. Only later did it become clear to most reviewers that Kosiński was neither the boy in the story nor did he share any of the boy's experiences, as revealed in a series of articles in newspapers and books.(2)[16] The depicted events are now widely known to be fictional.

https://en.wikipedia.org/wiki/The_Painted_Bird