The ex-IRS official whose emails mysteriously disappeared amid a congressional investigation into the Tea Party targeting scandal cautioned her own staff about "what we say in emails" during an internal discussion last year, according to emails obtained by Fox News.
Rep. Darrell Issa, R-Calif., referred to that discussion during a House oversight committee hearing on Wednesday, as he once again pressed IRS Commissioner John Koskinen on his concerns about ex-official Lois Lerner's missing emails.
He specifically voiced concern about an internal IRS chat system called the Office Communications Server, claiming Lerner wanted to make sure the messages weren't tracked.
This system was the subject of the emails between Lerner and other staffers in April 2013.
On April 9, 2013, Lerner, the director of Exempt Organization at the IRS, sent an email to IT employee Maria Hooke, asking about the OCS and whether Congress could access those messages.
"I was cautioning folks about email and how we have had several occasions where Congress has asked for emails and there has been an electronic search for responsive emails -- so we need to be cautious about what we say in emails," Lerner wrote.
She forwarded a question about whether the chat system conversations were also searchable.
Hooke responded that the messages "are not set to automatically save" but anyone could "copy and save the contents" to an email or file.
She recommended that the agency treat these conversations "as if it could/is being saved [somewhere], as it is possible for either party of the conversation to retain the information and have it turn up as part of the electronic search."
Lerner replied: "Perfect."
Republican lawmakers remain skeptical about IRS claims that Lerner lost her own email records after a hard-drive crash in 2011. The IRS notified Congress of the lost emails last month, but claims they've already been able to recover tens of thousands of emails by going to other accounts.
Lerner is at the heart of the controversy over the IRS practice of applying additional scrutiny to the applications of conservative groups seeking nonprofit status.
Lerner has twice refused to answer questions during appearances before Congress, citing her Fifth Amendment rights.
Fox News' Chad Pergram contributed to this report.