In light of Donald Trump’s kowtow to Vladimir Putin in Helsinki last summer; or the Trump Organization’s well-known crutch of Russian money; or firing of former FBI Director James Comey for “the Russia thing”; or concealing the substance of his meetings with the Russian president or countless other instances of pro-Russia behavior from this president, it may be shockingly unshocking that the Federal Bureau of Investigation opened a counterintelligence investigation into the president of the United States for being a Russian asset.

While this news is in some ways unsurprising, word of the FBI’s investigation is anything but boring. The public should understand the painstaking internal deliberations that lead to the investigation, what sorts of information it might have gathered, and how it could establish obstruction of justice charges against Donald Trump.

I began my career as an intelligence analyst not long after Sept. 11, 2001, working for the Naval Criminal Investigative Service, the agency made famous by the TV show your father loves.

But NCIS is also a very real and very serious national security agency, an FBI of the high seas, with overlapping law enforcement and intelligence-gathering mandates. Over the course of five years, I participated in my fair share of counterterrorism and counterintelligence investigations.

Investigations are the lifeblood of law enforcement, so much so that the word is engrained in the names of agencies such as NCIS and the FBI. While many go nowhere, the decision to open any investigation is serious business. If a federal agent is privy to information of a crime—or in this case, an individual serving the interests of a foreign government—the agent assembles the initial findings and presents them to a supervisor, who decides that the allocation of taxpayer resources in pursuit of additional collection (the investigation) is in the public interest.

It’s that first pitch to the boss that really counts, because the initial evidence must be credible enough to continue. Available evidence that Trump is working to advance Russian interests—much of which I listed above—is so embarrassingly obvious and so blindingly public, that it essentially forced the FBI’s hand to wonder whether more was happening in private. Hence, the initial information was deemed credible enough to warrant further inquiry.

Bureaucratic process demands that the higher an investigation’s profile, the more it’s scrutinized from above. Green-lighting an investigation of the president of the United States of America, much less one suspected of being a Russian agent, would have certainly gone all the way to the top.

Former acting FBI Director Andrew McCabe (briefly installed after Comey’s dismissal before being fired himself), Deputy Attorney General Rod Rosenstein, and then–Attorney General Jeff Sessions would have all known about the investigation. Sessions would have informed congressional leadership, Director of National Intelligence Dan Coates, and then–CIA Director Mike Pompeo. It is simply inconceivable otherwise.

Pompeo, now secretary of state, stammered his way through an interview with Margaret Brennan on Face the Nation last weekend when Brennan asked whether he was aware of it.

“Margaret—Margaret—Margaret,” Pompeo said, “I’ve answered this question repeatedly indeed on your show. The—the idea that’s contained in the New York Times story that President Trump was a threat to American national security is—is silly on its face and not worthy of a response.”

It’s testament to the investigation’s gravity that so many of the highest-level Cabinet officials and members of Congress must have known of its existence yet remained silent about it. Its existence has only now been confirmed because “former law enforcement officials and others” fear this significant data point could get buried in the coming deluge of information that may accompany the end of Robert Mueller’s investigation.

Virginia Sen. Mark Warner, the ranking Democrat on the Senate Intelligence Committee, has already said that Trump’s curious actions in Russia’s interest are the defining issue of his chamber’s investigation. Warner’s gavel-wielding, Democratic House colleagues suddenly find themselves in a powerful position. They can call former acting FBI Director Andrew McCabe and former Attorney General Jeff Sessions to testify publicly about the length, breadth, and depth of the Trump counterintelligence investigation. Their testimony will further establish its merits and scope at least, as well as answer the two crucial and age-old questions of presidential inquiries: Did Trump know he was under investigation? And when did he know it?

Those answers will help establish whether the investigation’s existence motivated Trump to brow-beat, and subsequently fire, McCabe and Sessions. In turn, it will help us understand the credibility of another key charge against Trump: obstruction of justice.