Greta Boyen was a neighbor to the Shields family and was married to Greg with the two of them later having an unnamed son. At some point, while Michaela Shields was overseas, Greta, presumably seeking comfort and bored with her life began having an affair with Shields's husband, David. David later opted to end the affair much to Greta's dismay. Fueled by revenge and believing that David would come back to her once the Commander was dead, Greta began creating a bomb which she planted in an unmarked car, hoping that once it went off, it would result in the Commander's death.