The Case of the Abandoned Warehouse (Mystery House #2

When Ellen and her two best friends travel to Tulsa for Sue's daughter's wedding, they get the crazy idea of flipping another historical home—only this time, it's an abandoned warehouse. When they hear from the locals that the place is haunted, Ellen and Sue convince Tanya to investigate, and what they uncover is one of Tulsa's and the nation's most horrifying secrets.