When I say "criminal behavior" I don't mean "war crimes", although there are plenty of those that need to be addressed.
Instead, I'm talking about "behaving like a criminal" in a law enforcement sort of way.

The U.S. Department of Defense is reportedly still funneling billions of dollars’ worth of Soviet-era weaponry to anti-Islamic State groups in Syria, with questionable oversight.
In a joint report published Tuesday, the Organized Crime and Corruption Reporting Project (OCCRP) and the Balkan Investigative Reporting Network (BIRN) allege that the Pentagon has given up to $2.2 billion worth of weapons to groups like the Syrian Democratic Forces and the Kurdish People’s Protection Units, or YPG.

So far this story is a scandal, but not a shocking one. It's what one might expect.
However, the next couple paragraphs cast the news in an entirely different light.

The program sidesteps long-established checks on international weapons trafficking, the report alleges, and appears to be turbocharging a shadowy world of Eastern European arms dealers.
In particular, the Pentagon is reportedly removing documentary evidence about just who will ultimately be using the weapons, potentially weakening one of the bulwarks of international protocols against illicit arms dealing.
“The Pentagon is removing any evidence in their procurement records that weapons are actually going to the Syrian opposition,” Ivan Angelovski, one of the report’s authors, told Foreign Policy.

What sort of organization destroys documents to hide its activities?
A criminal organization.

Legally, however, shipments like the ones that started flowing to groups in Syria are supposed to include information on the end-user of the weapons. Instead, according to the report, the Defense Department decided to allow the transfer of equipment to any army or militia it provides security assistance to — including Syrian rebels — without any clear documentation.
...The United States is “undermining the object and purpose” of the U.N. Arms Trade Treaty, Patrick Wilcken, an arms control researcher at Amnesty International, told the investigators. Another expert on conflict prevention said U.S. manipulation of the system could put the the entirety of the international arms control regime at risk.
In addition to the potential legal consequences of the Pentagon’s program, the report also documents issues with the acquisition process itself.
According to the report, many of the weapons suppliers — primarily in Eastern Europe but also in the former Soviet republics, including Kazakhstan, Georgia, and Ukraine — have both links to organized crime throughout Eastern Europe and spotty business records.

This is outrageous! We should be throwing generals in jail right and left for this.
This is a rogue organization undermining national security.
Instead, it's just an obscure "report".

I've just got fired for telling the truth about weapons supplies for #terrorists in #Syria on diplomatic flights https://t.co/wSJTRIzKnr

— Dilyana Gaytandzhiev (@dgaytandzhieva) August 24, 2017

No government agency gets away with sh*t the way our military does.
For instance, remember this from last year?

The Defense Department’s Inspector General, in a June report, said the Army made $2.8 trillion in wrongful adjustments to accounting entries in one quarter alone in 2015, and $6.5 trillion for the year. Yet the Army lacked receipts and invoices to support those numbers or simply made them up.
As a result, the Army’s financial statements for 2015 were “materially misstated,” the report concluded. The “forced” adjustments rendered the statements useless because “DoD and Army managers could not rely on the data in their accounting systems when making management and resource decisions.”
Disclosure of the Army’s manipulation of numbers is the latest example of the severe accounting problems plaguing the Defense Department for decades.

If SNAP made up a couple million dollars in its books, it wouldn't be called a "severe accounting problem".
It would be called fraud. But rules don't apply to the MIC.