Authorities are detaining a 12th, previously undisclosed person implicated in the federal probe that busted a Cold War-style Russian spy ring, according to a U.S. official familiar with the matter, The Wall Street Journal reported.
Federal Bureau of Investigation counterintelligence investigators have been investigating the 23-year-old Russian man since last fall when his name surfaced in a decade-long espionage investigation, the official said.
Prosecutors in the Manhattan U.S. Attorney's Office last month charged 11 people with being agents of Russia's SVR foreign intelligence agency.
Ten in U.S. custody entered plea deals last Thursday as part of a diplomatic agreement to swap them for four people held by Russia, most on charges of spying for Western intelligence agencies.
It's unclear what drew investigators' interest in the 12th man, but FBI agents began monitoring him shortly after he entered the U.S. in October 2009, the official said.
The man, whose name couldn't be learned, obtained a U.S. visa in August 2009, the official said.
However, investigators weren't able to gather enough evidence against him to bring charges and came to believe his case was different from that of the others who ended up being charged the spy ring, the U.S. official said. It's not clear whether he had the training of the others arrested.
Instead of being charged, the man was in federal custody Monday in the process of being deported, the U.S. official said. His location wasn't disclosed.
U.S. officials on June 26 canceled the man's visa. A day later, FBI agents rounded up 10 of the 11 members of the spy ring who were in the U.S. The 11th person jumped bail in Cyprus after he was arrested there.
Details of the newly disclosed man's movements in the U.S. couldn't be learned.
The revelation comes on the heels of a historic prisoner swap carried out last Friday on the tarmac of the Vienna airport. The U.S. turned over the 10 Russian undercover agents it had arrested, while Russia exchanged four prisoners it held.
The swap marked a quick end to an embarrassing episode that threatened to set back improving U.S.-Russian ties.
The 10 long-term Russian agents arrested pleaded guilty last week to federal charges of conspiring to act as illegal foreign agents and agreed to be expelled from the country.
Since the Vienna swap last Friday, the 14 agents involved have remained out of public view in Russia, the U.S. and the U.K., where two of the prisoners held by Russia chose to go. All the agents are expected to undergo lengthy debriefing by intelligence officials before being allowed to move freely.
U.S. authorities said the minor children of the 10 arrested by the U.S. have been sent to Russia to join their parents.
The Manhattan U.S. attorney's office, which prosecuted the case of the Russian spy ring, alleged that the agents were part of a program run by Russian intelligence to plant sleeper agents in the U.S.
The agents' mission in part was to become Americanized and infiltrate policy-making circles to help identify people that the SVR could target for spying.
Prosecutors laid out a case seemingly lifted from the pages of spy thrillers, saying that the agents used a variety of secretive methods to conceal their identities-some high tech, others less so.
They allegedly handed off money in a "brush pass," exchanging identical orange bags at a railroad station in Queens, buried money in the ground for someone else to dig up two years later, and posted hidden notes on websites for the "Center"-headquarters for the SVR., the Russian intelligence service-using a method called steganography.
The FBI carried out the arrests on June 27. Within 10 days, U.S. and Russian officials had negotiated the spy swap deal.