Spoilers ahead. You’ve been warned.

Heroes in Crisis is one of the biggest ongoing mysteries in comics, which is why the penultimate issue out today revealing the killer comes as a big shock. Surely Tom King wouldn’t reveal his whole hand in the second to last issue! Chances are he hasn’t, but he has revealed quite a bit. Heroes in Crisis #8 reveals why the murders took place, but even more importantly why the mystery began at all.

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On the opening page, it’s already made clear who committed the murders. . .

But why? Why would Wally West do such a thing? Over the course of the issue Tom King, Mitch Gerads, and Travis Moore reveal it might have been an accident.

Using his speed Wally essentially uses the machines in Sanctuary to collect every piece of data, confession, and horror revealed to Sanctuary. In a few seconds, Wally saw too much and it breaks him.

As King puts it this makes Wally lose control and. . .

Some might be reminded of Hal Jordan’s turn to madness in the “Emerald Twilight” storyline ultimately going mad after hearing the voices of those killed crying out in his mind.

It’s an accident to be sure and it’s one that occurs in part because Sanctuary made it so. What follows, however, is no accident. Harley Quinn and Booster Gold have thought from the beginning they knew who the killer was, but Wally set them up.

That’s where the mystery basically started and why the two main protagonists have been so far off.

Later on, there are interesting time travel elements introduced, but I won’t spoil those here. The important thing however is knowing Wally is the culprit not only of the deaths but why there is a mystery at all.

No, instead I recommend you pick up this issue and get the whole story. It’s out digitally today.