Asha Rangappa is a senior lecturer at Yale's Jackson Institute for Global Affairs. She is a former special agent in the FBI, specializing in counterintelligence investigations. Follow her @AshaRangappa_. The opinions expressed in this commentary are solely those of the author.

Critics of Mueller's investigation have been quick to suggest the indictment proves that no collusion took place between the Trump campaign and Russia. President Donald Trump reiterated as much in a string of tweets on Saturday and Sunday, in which he argued yet again "that the only Collusion was between Russia and Crooked H, the DNC and the Dems" and that the Russians "are laughing their asses off in Moscow!"

And although this indictment does not make the allegation of Trump campaign collusion explicitly, it may be too early to jump to any definitive conclusions. As a lawyer and former FBI agent who conducted counterintelligence investigations, I believe Mueller achieved five things with this indictment, all of which suggest this is not the end of the story.

1. Neutralizing Russia

The most extraordinary aspect of Mueller's indictment is that it lays out, in great detail, one aspect of a large-scale Russian intelligence operation against the United States. It's not surprising that the FBI uncovered the operation: As part of its counterintelligence mandate, the FBI's job is to identify and disrupt the activities of foreign spies in the United States.

Typically, however, these investigations never see the inside of a courtroom. That's because it's generally better for the FBI to keep its adversaries from knowing they are monitoring their activities: This allows the FBI to keep its methods and sources secret and quietly "neutralize," or render ineffective, the foreign intelligence service's operations.

In making the details of Russia's social media and propaganda operation public, Mueller accomplished two goals. First, he made it crystal clear to Russia that pursuing a criminal case against individuals and entities who have interfered in our democracy is a priority and worth the tradeoffs that come with exposing the FBI's secrets. And second -- and perhaps more importantly -- because Russia's social media and propaganda campaign is only effective as long as it remains in the shadows, the best way to neutralize it is to make it public. Mueller's indictment reveals exactly how Americans may have been duped by false and misleading information pushed out by Russia.

2. A public 'report'

One of the limitations of the special counsel regulation is that it focuses on a criminal investigation, not a counterintelligence one. This means that beyond charging specific violations of the federal criminal code, Mueller does not have an option to provide a public report laying out the bigger picture, in the same way that former independent counsels, like Kenneth Starr, had the power to do. (Starr, referred to as independent counsel -- not special counsel -- had more latitude, but after his investigation concluded, new Department of Justice regulations were written to reel in the excesses of his investigation.) Without a report coming from the lead investigator, the American public would have to rely on Congress to investigate the matter thoroughly.

It's fair to say that neither the House Intelligence Committee, the Senate Intelligence Committee nor the Senate Judiciary Committee -- all of which are ostensibly investigating alleged Russian interference -- have helped the American public make sense of what happened in 2016. Mueller's indictment now fills this void. The indictment identifies the federal crimes Russian individuals and companies may have violated, including conspiracy to violate federal election laws, wire fraud, bank fraud and identity theft.

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Though it's unlikely that Mueller will be able to bring these defendants into court (since Russia will probably not extradite them), focusing the charges on Russians allows him to use the indictment as a kind of "public report," which gives the bigger picture of what Russia attempted to do. The indictment supplements the January 2017 intelligence community assessment that Russia did interfere in the 2016 elections and shows that there is hard evidence to prove that this allegation is not a hoax.

National security adviser H.R. McMaster acknowledged as much, telling an audience in Germany on Friday that Mueller's indictment shows Russian meddling is "now really incontrovertible." Trump tweeted in response that McMaster forgot to say "that the results of the 2016 election were not impacted or changed by the Russians" -- undercutting his adviser's strong rhetoric.

3. The groundwork for collusion

As I have written previously , Mueller's path to proving collusion is 1) identifying what the Russians did; 2) determining if they violated any federal laws; and 3) finding evidence that US persons helped Russia in its efforts. The indictment shows that Mueller has found evidence of (1) and (2). The indictment also shows that Russia did enlist the help of US persons in several aspects of its operations. These include "unwitting" members of Trump's campaign involved "in local community outreach ... that supported then-candidate Trump."

The fact that the indictment states that some members of the campaign were "unwitting" does not preclude the possibility that Mueller has evidence that campaign members wittingly assisted Russia as well.

The key here is the charge of "conspiracy," which is the legal term for "collusion." Anyone who knowingly helped Russia in any aspect of its operation can be charged with conspiracy -- or aiding and abetting the conspiracy. Remember that Mueller can always amend or "supersede" the indictment to include additional defendants. In fact, the introduction to the indictment indicates that Russians conspired with "persons known ... to the grand jury" -- which may include American defendants who have already been charged or are under investigation.

4. Encouraging people to come forward

Given that Mueller can always charge additional defendants, the indictment puts anyone who knowingly assisted Russia on notice that they may be next. This could include members of the Trump campaign, social media executives or ordinary Americans, all of whom now know that Mueller has substantial evidence in his possession, including detailed communications between Russian operatives and people within the United States. These individuals now have an opportunity to come forward -- and perhaps receive more lenient treatment than if they stay silent.

It's also noteworthy that the indictment focuses only on one aspect of Russia's operation, namely its social media and propaganda campaign. But the intelligence community has also indicated that Russians attempted to hack the DNC server and made attempts to offer stolen emails to the Trump campaign -- which could constitute additional federal offenses.

Mueller is undoubtedly investigating these aspects of Russia's interference efforts. If Mueller is able to follow the 1-2-3 outline, additional conspiracy charges on these fronts may still be forthcoming.

5. Protecting the investigation

By charging only Russians and Russian entities in his indictment, Mueller has undermined allegations that this is simply a politically motivated investigation. In fact, by showing that the 2016 election interference was conceived and executed primarily by Russia, he has made clear that, at its core, this is a national security investigation against a hostile foreign power.

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At this point, there can be no question that trying to derail Mueller's investigation -- including attempting to fire him, or his boss, Deputy Attorney General Rod Rosenstein -- is directly beneficial to Russia. In short, the political costs of trying to quash the investigation have just skyrocketed, and attempting to quash the investigation at this point could even be a clear case of obstruction of justice.

In short, Mueller's latest indictment is just the beginning. He has identified a critical national security threat, publicized it and made it clear that he will pursue his investigation to the fullest extent of the law.