At 6:42 one morning, Wendy heard her 11-year-old daughter, Carly, screaming from the front yard. She rushed outside in slippers, expecting to find the small wooden library Carly had spent two weekends building smashed beside their mailbox. Instead, the pale-blue box and its crooked yellow roof were untouched. Even the painted paw print—the accidental “logo” created by the  familydog—remained near the bottom. But behind several displaced books, Carly discovered a plastic sleeve containing a handwritten warning: “REMOVE THIS.” The anonymous writer called the library an eyesore, complained about foot traffic, and ended with three chilling words: “YOU WERE WARNED.”Only 12 hours earlier, neighbors had filled the library with mysteries, children’s stories, and gardening books, while Carly proudly watched every visitor. Wendy’s husband, Dean, found no damage and no official name attached to the complaint. Then Wendy noticed that Melissa, a neighbor who had publicly praised Carly’s $60 project and donated three books, had deleted a Facebook comment questioning whether the library would attract strangers. Melissa privately advised Wendy to take the warning seriously, making Dean suspicious. Later, another anonymous message appeared beside a highlighted copy of the neighborhood guidelines—even though the library violated no rule. When Wendy posted  photographs of both warnings online, Melissa made one revealing mistake that exposed who had been visiting the library after midnight.