SPOILER WARNING: The following article contains major spoilers for Heroes in Crisis #8 by Tom King, Mitch Gerards, Travis Moore and Clayton Cowles, on sale now.

The ending of Heroes in Crisis #7 pointed the finger at the likely suspect behind the massacre at Sanctuary, and the latest issue confirms it. Tom King and Mitch Gerards' Heroes in Crisis #8 serves as an issue-long confession in which the killer acknowledges responsibility for the murders. It doesn't stop there, though. The killer also puts forth exactly how he pulled off such a murder spree, and why.

And, as long believed by many, neither Harley Quinn nor Booster Gold are the culprit. So, who is?

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Who Did It?

The murderer is none other than, yes, Wally West, former Kid Flash who now calls himself The Flash, who only recently returned to DC continuity at the beginning of Rebirth.

But what about Harley, who was seemingly caught red-handed by Booster, murdering Wally? And what about when exactly the reverse happened, one issue later? Wally was initially believed to be one of the massacre's highest profile victims, so how is he now back, claiming responsibility?

Wally explains all in his confession, one of the many recorded video transcripts that Wally himself sent to Lois Lane, while identifying himself as "The Puddler." And his explanation is a complex, tortuous path littered with screw-ups, setups and cover-ups.

How Did He Do It?

In his confession, Wally laments how he's felt "alone" since his return. Understandable, as his family remains wiped from existence, with no one even to remember them, except him. These tortured memories are what led him to Sanctuary at the end of "Flash War," but he found no comfort there. He relates how he still felt alone because he didn't see the same kind of pain in its other residents, and the program's anonymity only compounded his feelings of isolation.

Wally therefore did some digging of his own into Sanctuary's resident records and uncovered a truth that he had been denying. Every one of the heroes at Sanctuary were in fact coping and trying to overcome their own personal traumas, just as Wally was. Uncovering all this information at superspeed led to a flood of emotional experiences that momentarily allowed Wally to understand he wasn't so alone after all.

While this realization might have initially given Wally some comfort, it all came to him in a comparative instant. Instead of helping to heal him, the onslaught of emotions broke him. In turn, he momentarily lost control of the powers of the Speed Force contained within him. And in another fateful instant, the powers of the Speed Force were unleashed on the other heroes within Sanctuary, killing them instantly.

NEXT PAGE: Heroes in Crisis' Time Travel Adds an Extra Layer to Wally's Tale

How Did He Get Away With It?

But what of the various and sundry ways the heroes appeared to be killed, as shown in series' first issue? And how does this inconsistency tie into Harley and Booster's apparent involvement?

Wally accessing Sanctuary's files had tripped the facility's alarm, and the moment of Wally's breakdown happened to occur while Harley and Booster were immersed in their respective virtual reality therapy sessions. Taking advantage of that happy coincidence, Wally used his powers to deliver a superspeed sleight of hand at Harley and Booster's expense. As each exited their VR chambers, he reprogrammed them and tricked the pair into thinking they had left the chambers, when in fact they had not.

Instead of seeing the actual massacre, what each instead saw was the other murdering Wally. That's right, both opposing scenarios were actually VR simulations. Neither Harley nor Booster had killed Wally, or anyone else for that matter.

From there, Wally stole Booster's time traveling tech, went five days into the future, killed his future self and brought his future body back to present day to leave at the scene. Wally's machinations are what led Booster to discover that dead Wally's body was five days too old. Wally then relocated all the bodies of the others he had slain, staging the murders to place himself above suspicion, and set up Harley and Booster as the prime suspects instead.

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To complete the subterfuge, Wally then destroyed Sanctuary's computer and robot attendants, and scribbled the now infamous "The puddlers are all dead" on Sanctuary's living room wall. He successfully misdirected everyone involved in the investigation, but why?

Why Did He Do It – and What's Next?

As Wally explains, "puddlers" traditionally are the metal craftsman who remove impurities from molten metal, making it ready to forge. Wally sees himself as "The Puddler" because he has removed, albeit inadvertently, the "impurities" from the superhero community. The other flawed heroes with problems, the ones who needed help, including himself, are now gone.

Wally's assumption of The Puddler role wasn't intentional. He didn't mean to kill anyone, he only did so accidentally in a moment of weakness. If Wally's a hero, though, why didn't he just come clean immediately after the inadvertent massacre? Why go through all the deceit, the framing of two other characters and, most notably, killing his own future self?

In a sense, Wally delivered justice, albeit vigilante justice, against himself. At issue's end, his explanation and justification for his elaborate actions is to place himself above suspicion, allowing himself the opportunity to offset what he's done by doing something good in the five days he has left. But what could Wally possibly do that would redeem himself after murdering so many heroes and then covering up his actions?

With time travel now introduced as an element of the story, almost anything is possible. Might Wally travel back in time before the massacre and prevent it entirely? Or, in his broken state, does he have something more questionable in mind? The story concludes in Heroes in Crisis #9, on sale May 22.