I'll be annotating my sources differently in this article; instead of using essay-style MLA format as I've done for several years, I'll be listing them as footnotes the way I do in my books.

So, the world's foremost slayers of civilians (Russia) have watched 140 of their civilian neighbors die in a terrorist attack on a concert hall(1). And of course, the terrorist population of Russia simply can't grasp why the families of the hundreds of thousands they've massacred in Ukraine are not falling over themselves in sympathy. Meanwhile, at exactly the moment when Vladimir Putin was beginning to lose his vice-grip on public opinion in Russia and face opposition to his genocidal war in Ukraine, how fortuitous for him that exactly the attack he needed in order to sway the public back behind him just happened to happen.
Predictably enough, Russia's State Media were quick to come out and insist "it was the US, the UK and Ukraine who were behind it,"(2) which means it will be a matter of scant hours before Putin's faithful and unquestioning worshipers in the West like @valued-customer and @vp-freelance, who never miss an opportunity to cheer for mass murder, post articles here on Hive claiming that this declaration (without a single shred of evidence of course) by the Russian State is some sort of "proof" that Russia's ongoing genocide of Ukrainians is a "heroic struggle" to defend itself and that the Ukrainian children they've been slaughtering for two years now have been "NATO-backed terrorists." So, since it's a foregone conclusion that these reptiles will be slithering out into the open to faithfully echo the message of their master in the Kremlin (EDIT: Proven in the comments, where @vp-freelance tried the usual pack of trite an warmed-over Krem-slogans about how Ukraine, which has never attacked a nation in its 1,200 year history, somehow started the war), it seems prudent to go ahead and lay out some ironclad facts that prove that the Kremlin's narrative, as usual, makes no sense.

First, Here's What Happened.

From March 7 onward, the United States Embassy in Russia (which for some reason is still operating after more than 30 Russian threats in two years to launch nukes at America) issued warnings that a terrorist attack in the Moscow area was imminent by the same ISIS cell France had already foiled several attacks from in recent months (even if the Biden Administration did predict the attacks too early, just as they did with Russia's Ukraine invasion). Russia dismissed these warnings as fearmongering.(3)
On March 24, four men in highly-conspicuous jungle camouflage, from Tajikistan (a staunch Russian ally)(4), stepped out (in full view of dozens of cameras in broad daylight) into a concert hall in Crocus City Hall in the Moscow Metroplex. They casually opened fire for long enough to kill 140 people while security forces in the most tightly policed city in Russia did nothing to stop them. They then got into the same car they arrived in, made no efforts to change their clothes or hide themselves and, at great efforts to draw as much attention to themselves as possible, sped conspicuously down the most heavily-surveilled highway in Russia, leading toward the heavily-guarded Russo-Ukrainian border. As one commenter put it, "it’s as if they wanted to be caught."(5)
An ISIS offshoot known as ISIS-K immediately claimed credit for the attack, and Al-Jazeera (a network not really known to be fond of Russia, Ukraine, the West or ISIS) pointed out a rather cogent list of reasons why this made perfect sense.(6) Russia, however, insisted that this confession was false and that they knew who was really behind the attack. The Russian FSB then, in a suspiciously uncharacteristic move, released a video of their interrogation of one of the gunmen(7), where in he can be seen reading a confession off of a teleprompter.
In a staggering coincidence, all four brutally tortured gunmen confessed on exactly the same day (take it from a former police interrogator; that doesn't happen), to exactly the same narrative, namely, that they'd been hired by Ukrainians.(8) Russian State Media also claimed that the US's quick decision to blame ISIS proves that the US was involved, rather than that the intelligence the US had already provided pointing to an upcoming attack by ISIS was in fact accurate. The head of the FSB then stated there had been mountains of evidence beforehand linking Ukraine to the attack, though he declined to cite any of this phantom "evidence" except to insist there was plenty of it.(9)
And finally, there are rumors that Vladimir Putin plans to pardon the attackers.(10)
Now, there are plenty of obvious problems with this story.

1) If the West was involved, why did we warn Russia so far in advance? Despite Russia's insistence that there had been no warnings from the West, the warnings he'd been given are still on public record,(11) along with Putin's insistence that they were false. If the West was planning to back a large-scale terrorist attack on Russian soil, broadcasting so many warnings about it for a month in advance doesn't make much sense, does it?

2) Why Was Nothing Done? There's no place in the Russian Federation where security is tighter than it is in Metro-Moscow. In fact, Crocus City Hall itself is four minutes away from the home base of Moscow's riot-control police. So where were the police? And why does security footage show absolutely zero resistance from the hall's armed security force? Shooting 140 people isn't a hit-and-run. These four men had to be in place continually shooting for quite some time to inflict a body count like that. This smacks of security forces being told to stand down (and we'll get around to asking why later).

3) Why Didn't They Hide Themselves? Russia's own State Media reported that if the attackers had changed their clothes they could easily have blended in with thousands of other migrants in the area. Why didn't they? And why would they get into the same car so many cameras had seen them get out of, and speed down the most heavily surveilled highway in Russia? Again, "it's as if they wanted to be caught."

4) Why Is Putin Pardoning the Gunmen? Russia is not known for its mercy. Their history of swift and brutally lethal vengeance is one of the few defining traits they have that could be called a cultural identity. Why is Putin, whose M.O. is to vow swift and bloody retaliation for the smallest slight, calling for mercy? The obvious answer is "because the attackers were acting on his orders (orders we'll get to later) and they've finished their job."

5) Why Can't Putin and Lukashenko Keep Their story Straight? While Putin insists the attackers sped toward Ukraine where they had a pre-prepared reception waiting for them, Lukashenko insists they originally sped toward Belarus but swiftly changed direction when they got near the border.(12) This alone is a red-flag. The Russo-Ukrainian border is one of the most heavily-guarded borders in the world (due to, you know, the fact that they're at war), while the Russo-Belarusian border is as lightly guarded as most inter-state borders in the EU due to both nations being part of the so-called "Union State." Entering Belarus would have been far easier. So, why the last-minute change of direction toward a border no vehicle can approach without passing through the lines of fire of at least forty tanks? The answer is "because their handler in the Kremlin decided there was not yet enough evidence to provide the Ukraine-connection he needed."

6) Why Did All Four Gunmen Confess Simultaneously, Quickly, and with Pre-Written Confessions on a Teleprompter? As a veteran interrogator I can attest from experience that getting all the conspirators in a crime to confess to the same details at the same time simply doesn't happen, and it damned sure doesn't happen in a matter of days like this, especially when the known penalty for guilt is at best life imprisonment and at worst death. The gunmen had no incentive to confess a thing when they know for a fact they're going to rot in jail if they confess. Unless, of course, their confessions were coerced by torture and they were told "you can go free when we hear what we want to hear," as was stated above.

7) Most Importantly, Quis Prodest (Who Benefits)? The attack didn't have any military benefit for Ukraine, nor any political benefit for the West. It didn't damage Russia's war effort. There's not really a situation wherein it could have. 140 civilians at a concert isn't going to reduce Russia's conscription pool. The claim that Ukraine was behind it begs the question of "to what point and purpose?" If Ukraine was able to sneak four heavily-armed gunmen that close to Moscow, why not sneak them into a petrochemical refinery instead where that same ammunition could have blown an entire plant sky-high, which actually would have aided Ukraine's war effort? There's no motive.
The West doesn't benefit either. If a military alliance whose combined defense budget exceeds Russia's GDP three times over wanted to damage Russia, why would we have bothered targeting a concert?
The only beneficiary, is Vladimir Putin. His war machine hasn't been damaged, but at a time when the Russian people were suddenly beginning to rise up against him and some were even openly siding with Ukraine,(13) all of a sudden the Russian population now has something to get mad about again, and by blaming Ukraine, the Russian population's faltering support for the genocidal war has been fanned right back into a flame. Think of how Hitler benefited from the Reichstag bombing, or how so many of the conspiracy theorists I'm aiming this article at believe G. W. Bush benefited from the 9/11 attacks.

Nothing New

It's not like this tactic of "engineer an attack on your own civilian population in order to gain support for a war" is new or unheard of for Russia, or even Putin himself. Remember 1999, when a series of bombings at low-value civilian targets all across Russia gave Putin the support he needed to drag Russia into the Chechen War?(14), (15) I'm calling it. Putin, who was losing his grip on the Russian population, needed something to bring them back into line. So, when he heard Western sources warning him "hey bro, ISIS is coming after you," he insisted this was false and ordered his men to let the attacks (which inspired plenty of anger and hate across Russia but conveniently didn't damage its ability to fight) continue, and conjured up rather dubious claims of Ukrainian involvement, thus insuring the Russian people's renewed support. There's even some grounds to wonder if he intercepted and co-opted the shooters, as indicated above. I'm not the only one suspecting this either. There are plenty in Russia who have smelled the same rat. (16)
But of course, the same people who are quick to insist that Pearl Harbor, 9/11, the Lusitania and basically every attack that has ever propelled the U.S. or Israel to war were false flag attacks, will be quick to insist that anyone asking questions about the dubious nature of Putin's claims here, is "being a Western stooge." Because after all, one who claims to be a "FrEe ThInKuR" is not supposed to mindlessly accept the media narrative...
...Unless, of course, it's the Russian media narrative.

And sadly, there are plenty of people in America who are stupid enough to do just that.

Sources

(1) "Moscow concert hall death toll reaches 140." RT (Russian State Media). 27 March, 2024. Accessed. 27 March, 2024.
https://www.rt.com/russia/594998-moscow-concert-hall-death-toll-140/

(2) "US, Britain, Ukraine behind Crocus City Hall attack — FSB chief." Tass (Russian State Media). 26 Mar, 2024. Accessed 27 Mar, 2024. https://tass.com/emergencies/1766181

(3) "Moscow Terror Attack Timeline: Before Shooting, US Warnings and a Putin Dismissal." Deccan Herald. 26 March, 2024. Accessed 27 MArch, 2024. https://www.deccanherald.com/world/moscow-terror-attack-timeline-before-shooting-us-warnings-and-a-putin-dismissal-2952457

(4) Heintz, Jim. "Russian massacre suspects' homeland is plagued by poverty and religious strife." Washington Post. 25 March, 2024. Accessed 27 March, 2024. https://www.washingtonpost.com/world/2024/03/25/russia-shooting-concert-hall-islamic-state-tajikistan/4b07a632-eac7-11ee-8f2c-380a821c02db_story.html

(5) Colibansu, Antonia. "Fallout From the Attack in Russia." Geopolitical Futures. 26 March, 2024. Accessed 27 March, 2024.
https://geopoliticalfutures.com/fallout-from-the-attack-in-russia/

(6) "Moscow concert hall attack: Why is ISIL targeting Russia?." Al-Jazeera. 23 March, 2024. Accessed 27 March, 2024.
https://www.aljazeera.com/news/2024/3/23/moscow-concert-hall-attack-why-is-isil-targeting

(7) Simonyan, Margarita. "First interrogation of Moscow terrorist attack suspect (VIDEO)." RT (Russian State Media). 23 March, 2024. Accessed 27 March, 2024.
https://www.rt.com/russia/594774-simonyan-video-suspected-terrorist-interrogation/

(8) Times of India. "'Not ISIS': Russians Fume At U.S Media As Arrested Terrorists 'Sing' I Moscow Attack." Youtube

(9) "US, Britain, Ukraine behind Crocus City Hall attack — FSB chie." Tass (Russian State Media). 26 March, 2024. Accessed 27 March, 2024. https://tass.com/emergencies/1766181

(10) Hindustan Times. "Putin To Pardon Moscow Attackers? Russian Leader's New Message On Friday Attack, Appeal To People." Youtube. 26 March, 2024. Accessed 27 March, 2024.

(11) "Security Alert: Avoid Large Gatherings over the Next 48 Hours." * Ministry of the United States of America in the Russian Federation. 7 March, 2024. Accessed 27 March, 2024. https://ru.usembassy.gov/security-alert-avoid-large-gatherings-over-the-next-48-hours/

(12) Sherman, Ella. "Belarus' leader undermined the Kremlin's dubious claims that Ukraine backed ISIS attackers." Business Insider. 26 March, 2024. Accessed 27 March, 2024. https://www.businessinsider.com/belarus-leader-undermined-kremlin-claims-ukraine-backed-isis-attackers-2024-3

(13) Reevell, Patrick. "Alexei Navalny's funeral goes ahead despite pressure." ABC News. 1 March, 2024. Accessed, 27 MArch, 2024. https://abcnews.go.com/International/alexei-navalny-funeral-friday-moscow-despite-pressure/story?id=107684524

(14) Cockburn, Patrick. "Russia 'planned Chechen war before bombings'." The Independent. 29 January, 2000. Aarchived in Wayback Machine, accessed 27 March, 2024. https://web.archive.org/web/20090827150331/http://www.independent.co.uk/news/world/europe/russia-planned-chechen-war-before-bombings-727324.html

(15) Felshtinsky, Yuri & Pribylovsky, Vladimir. The Age of Assassins. The Rise and Rise of Vladimir Putin. London, 2008. Gibson Square Books. (pp. 105-111)
ISBN 978-1-906142-07-0

(16) Kika, Thomas. "Putin Critics Suggest Moscow Concert Shooting Was 'False Flag' Operation." Newsweek. 23 March, 2024. Accessed 27 March, 2024. https://www.newsweek.com/putin-critics-suggest-moscow-concert-shooting-was-false-flag-operation-1882714