It was Friday night when reports started coming in about a concert outside Moscow that had been targeted by terrorists. At first, the only images on social media were of the outside of the mall where the attack took place—a shooting, and then a fire. Then, there were videos from inside the venue—the sounds of gunshots and panic.

All weekend long, the Washington Post’s Shane Harris (no relation) was sorting through this evidence and trying to understand what exactly took place. He told me, “We’re seeing obviously a lot of reports via social media, including by people who were in the concert hall when it was attacked. We’re hearing from Russian officials who were on the scene investigating it, and who are issuing statements about body counts and sort-of objective things, and then maybe a separate category of not so objective information.”

All of those different sources—firsthand accounts, Russian investigators, American officials—do not agree about what took place.

At latest count, 137 people were killed, and more than 100 were injured. American officials say that Friday’s attack has all the hallmarks of ISIS, specifically ISIS-K, a branch of the Islamic State based out of Afghanistan. The Kremlin disagreed. “What we’re hearing coming out of President Putin and Russia as well as [from] Kremlin-backed or supportive broadcasters and journalists is an effort to try to blame this attack on Ukraine,” Harris said. But, at the same time, ISIS itself is taking credit.

In social media posts via ISIS-K’s own news agency, the terror group released gruesome footage allegedly shot by the shooters themselves in the concert venue as proof of their responsibility. “It’s almost as if ISIS is responding in some way to Putin’s unwillingness to give them credit for the attack, because part of what ISIS wants here is to undermine Putin and Russia’s security apparatus,” Harris told me, “If the president of Russia in his public address refuses to acknowledge who actually did the attack, it’s not giving ISIS the kind of public relations victory it was hoping for.”

On a recent episode of What Next, we spoke about the importance of this blame game. A portion of our conversation is transcribed below; it has been condensed and edited for clarity.

Mary Harris: This was in a concert venue, also a mall, called Crocus City Hall, on the outskirts of Moscow. What was this place?

Shane Harris: So this is a big, kind of glitzy concert hall and public event space, northwest of central Moscow, out in a suburb. Sia played there at one point; other big bands have played there. Folks were there on Friday to see an older Russian rock band called Picnic.

How did the attack start?

From what we understand, these gunmen walked into the event space, then got into the concert hall, and started shooting concert-goers. There have been these very gruesome photos that show them killing people, including one of them cutting a person’s throat, reportedly. From what we can see from the videos that have been posted, the gunmen were met with no resistance. There wasn’t a big security presence at the hall, there weren’t guards there fighting back against them. These terrorists were able to just go in and essentially, with free rein, terrorize this place. They appeared to spread some kind of flammable liquid that then set the concert hall ablaze and ultimately brought down the roof. So the attack really destroyed this venue, too.

How quickly did ISIS claim credit for what had happened?

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