Congress should investigate the ongoing failure of American counterintelligence to detect moles at the NSA, even if the latest incident turns out to be innocuous, a former agency analyst wrote Wednesday.

“The evidence that Russian moles are lurking inside NSA remains compelling,” former analyst and counterintelligence officer John Schindler wrote in a column for the Observer. “The FBI’s 2010 roll-up of 10 deep-cover operatives of the Russian Foreign Intelligence Service, or SVR … revealed the existence of multiple SVR agents deep inside NSA and the Defense Department. That was six years ago, and nobody’s been publicly fingered as any of those moles.”