Sanctuary has become a slaughterhouse. Designed as a place of healing, where heroes in need of support could work through the many issues that come with a lifetime devoted to fighting injustice, it’s instead become the site of one of the most shocking mass murders in history. But who’s responsible? All signs point to one of two people—Booster Gold or Harley Quinn. Each swears they saw the other do it, but who can be believed? Both are unreliable witnesses. Both have suffered remarkable trauma. Is it possible there’s something else at work here?In HEROES IN CRISIS #4, the Justice League attempts to get to the bottom of what happened, but that’s no easy task—especially since they’re dealing with the shock of the traumatic event themselves. Plus, do Booster or Harley truly have it in them to commit this sort of atrocity? They didn’t seem to, so if they do now, does that mean Sanctuary failed them? Is it possible that Sanctuary could have made things worse?In our exclusive preview of issue #4, Booster shares what he witnessed. His story seems credible, and he’s telling it while under the influence of the Lasso of Truth. But something tells us we shouldn’t be so quick to judge…