A law enforcement agent leaked three government documents detailing suspicious financial activity by the firm of Michael Cohen, President Donald Trump's personal attorney, due to concerns that information on Cohen's dealings were missing from a government database—a serious red flag pointing to the possibility that files detailing possible criminal activity were intentionally covered up, or that access to them has been restricted because Special Counsel Robert Mueller is investigating them.

The three documents, called Suspicious Activity Reports (SARs), came to light earlier this week when attorney Michael Avenatti, who represents the adult film actress who Cohen reportedly paid to keep quiet about her affair with the president, released a memo describing payments Cohen's firm had received, including $500,000 from a Russian oligarch and $200,000 from AT&T.

"As someone who worked at Treasury on anti-money laundering activities, my reaction to this Ronan Farrow story is 'holy s**t.'" —Daniel W. Drezner

The government whistleblower reported that two of the SARs regarding Cohen had vanished from a Treasury Department database, the Financial Crimes Enforcement Network (FINCEN), where such reports are listed.

Banks are required to file SARs when they detect transactions that may violate federal law, including ones that could indicate money laundering. Some payments made to Cohen were marked as "bribery or gratuity" and "suspicious use of third-party transactors (straw-man)" by banks.

"Things that stand out as abnormal, like documents being removed from a system, are of grave concern to me," the whistleblower told journalist Ronan Farrow, who first reported on the missing SARs in the New Yorker. "I have never seen something pulled off the system...That system is a safeguard for the bank. It's a stockpile of information. When something's not there that should be, I immediately became concerned."

Farrow wrote on Twitter on Wednesday evening that leaking a SAR is highly unusual and potentially dangerous for government agents.

The two missing SARs detailed $3 million in suspicious transactions by Cohen's company.

According to former government officials who spoke to the New Yorker, access to the two reports could be restricted due to their sensitive nature, as Cohen is currently under federal investigation as part of Mueller's probe—but such a restriction would be "nearly unprecedented."

"A former prosecutor who spent years working with the FINCEN database said that she knew of no mechanism for restricting access to SARs," wrote Farrow.