Security experts are focusing on 47 partially redacted emails from Hillary Clinton’s private server that discussed CIA personnel or operations, arguing the government may have inadvertently highlighted agency material for hackers with access to the original records.

A former National Security Agency official told the Associated Press Wednesday that, if any individual or organization had tapped into Clinton’s homebrew server and taken copies of her emails, the redactions denoted by the State Department as pertaining to the CIA would create a “key” for them to locate the names of CIA operatives.