Several media outlets reported this month on an alarming finding from a new U.S. government study: Iran's intelligence ministry, as CNN put it, constitutes "a terror and assassination force 30,000 strong."

The claim that the intelligence ministry has a whopping 30,000 employees, first reported by a conservative website, spread to other outlets including Wired and the public radio show the Takeaway and landed elsewhere online, even on the intelligence ministry's Wikipedia page. All cited the new government study, put out by an arm of the Library of Congress called the Federal Research Division.

So how did the government researchers come up with the number? They searched the Internet - and ended up citing an obscure, anonymous website that was simply citing another source.

The trail on the 30,000 figure eventually ends with a Swedish terrorism researcher quoted in a 2008 Christian Science Monitor article. But the researcher, Magnus Ranstorp, said he isn't sure where the number came from. "I think obviously that it would be an inflated number" of formal employees, said Ranstorp.

We inquired with six Iran experts, and none knew of any evidence for the figure. Some said it might be in the ballpark while others questioned its plausibility.

"Whether the figures emanate from Iran or from western reporting, they are generally exaggerated and either meant as self-aggrandizing propaganda, if self-reported by Iran, or just approximations based on usually scant data or evidence," said Afshon Ostovar, a senior Middle East analyst at the Center for Naval Analyses who writes frequently on Iran. The number "could be more or less accurate, but there's no way to know."

Gary Sick, a longtime Iran specialist in and out of government, said the entire Federal Research Division study "has all the appearance of a very cheap piece of propaganda and should not be trusted."

Sick pointed to the study's use of questionable Internet sources as well as flat-out errors. In one section, for example, the study lays out in detail how "Iran's constitution defines" the intelligence ministry's official functions. The problem, as Sick notes: Iran's constitution doesn't mention an intelligence ministry, let alone define its functions.

Federal Research Division Chief David Osborne said in an email the report "was leaked to the media without authorization" and declined to comment further "because it is proprietary to the agency for which it was written."

This is what we know about the 30,000 figure and its provenance:

On the morning of Jan. 3, the conservative Washington Free Beacon ran a story headlined, "Iran Spy Network 30,000 Strong." The outlet said it had obtained a "64-page unclassified report" on the Ministry of Intelligence and Security, and published it with the story.