Last year, Edward Snowden disappeared.
Eventually, he turned up in Russia.
Since then, the US government has been trying to answer a crucial question: is Snowden a lone wolf, or are other Edward Snowdens out there, leaking ever more classified documents?
The Feds now fear they have their answer, and it is in the affirmative: yes, it looks like there's at least one more mole in their midst.
The proof: an article posted Tuesday by The Intercept, a site run by Snowden leak publisher Glenn Greenwald.
The article references classified government documents obtained from somebody The Intercept describes as a "source in the intelligence community".
In the past, Greenwald hasn't shied away from naming Snowden as a source, leading many to the conclusion that this unnamed source is a new spiller of secrets.
The documents contain details about databases the government uses to track suspected terrorists around the world.
They were prepared by the National Counterterrorism Center and dated August 2013 - months after Snowden left the US to avoid criminal charges and while he was already far away, under asylum in Russia.
CNN has confirmed the authenticity of the documents with the government, it said in a newscast on Wednesday.
Unnamed "US officials" have also confirmed to CNN that national security officers fear that somebody in their own ranks is leaking classified intelligence - including not only these latest documents but also apparent NSA-related leaks contained in two articles published by the German magazine Der Spiegel last month.
According to the newly leaked documents, most of the people placed on the government's watchlist start out in an immense, classified database known as the Terrorist Identities Datamart Environment (TIDE) and are targeted using "far less evidence than the already lax standards used for placing people on the watchlist."
A US official confirmed to CNN that TIDE now contains 1 million names.
TIDE is passed around in the country's intelligence community, as well as being shared with commando units from the Special Operations Command and with domestic agencies such as the New York City Police Department, The Intercept reports.
The actual watchlist itself is a smaller, more select, but still extremely large group.
Known as the Terrorist Screening Database, or TSDB, it contains the names of some 680,000 people considered to be "known or suspected terrorists".
Fewer than 1% of those names are of US persons, and fewer than 0.5% are US citizens.
The TSDB is also widely shared, with local law enforcement agencies, private contractors, and foreign governments, in spite of it being made up of a large percentage - more than 40% - of people the government says aren't affiliated with terrorist groups at all.
In fact, those not affiliated with terrorists - they number about 280,000 - dwarfs the total number of watchlisted people whom the government suspects of having ties to Qaeda, Hamas, and Hezbollah - combined.
But exact numbers are hard to suss out.
Last month, the Associated Press reported that more than 1.5 million names have been added in the past five years, going by numbers divulged by the government in a civil lawsuit in Virginia disputing the constitutionality of the No-Fly List, a list created by the US's Terrorist Screening Center (TSC) of people forbidden from boarding commercial aircraft for travel in or out of the country.
But weeks later, a government official explained that the 1.5 million "nominations" for the watchlist included not only new names, but also changes or updates to existing names on the list, the AP reports.
Regardless of exact numbers, it's clear that the watchlist has grown ever more vast since the days it was stored in notebooks and a Rolodex.
It's also clear to many, including Greenwald and security blogger Bruce Schneier, who reviewed the Der Spiegel reports, that there's a second leaker at work getting this all out into the light of day.
Greenwald has expressed the opinion that it's likely that others would follow in Snowden's footsteps, inspired by Snowden's example.
Back when the NSA was claiming that Snowden pulled a fast one on at least one fellow NSA employee in order to gain access to the classified documents he leaked, Snowden denied the claims.
The concept that his example would inspire others is another matter entirely - one that I find pretty easy to swallow, given the outrage that Snowden's leaks have sparked and the demoralization within the ranks of US intelligence that's ensued.
We can't say, at this point, with 100% certainty, that there are other moles at work.
But it would be surprising if there weren't, given both the continuing leaks and the anti-surveillance zeitgeist.