Special Counsel Robert Mueller's investigation — and the reporting around it — is raising new questions about journalistic ethics in an era rife with fake news.

Why it matters: Protecting the relationship between reporter and source is a tenet of good journalism, but secrets and opacity can be tricky in times like these, when public distrust in politics and the media is ever-increasing.

Blogger reveals source

Marcy Wheeler, a prominent national security blogger who runs "emptywheel," revealed last week that she went to the FBI about a source she believed "had played a significant role in the Russian election attack on the U.S."

“On its face, I broke one of the cardinal rules of journalism, but what he was doing should cause a source to lose protection,” Wheeler told the Washington Post's Margaret Sullivan in an interview.

I broke one of the cardinal rules of journalism, but what he was doing should cause a source to lose protection,” Wheeler told the Washington Post's Margaret Sullivan in an interview. In her own words: Wheeler writes that she "never in my life imagined I would share information with the FBI, especially not on someone I had a journalistic relationship with." But that she chose to do so because she had evidence he was lying and "believed he was doing serious harm to innocent people."

Wheeler writes that she "never in my life imagined I would share information with the FBI, especially not on someone I had a journalistic relationship with." But that she chose to do so because she had evidence he was lying and "believed he was doing serious harm to innocent people." Wheeler said she received a text from the source 14 hours after the polls closed in November 2016. The text predicted that then-National Security Adviser Michael Flynn would meet with “Team Al-Assad” within 48 hours.

she received a text from the source 14 hours after the polls closed in November 2016. The text predicted that then-National Security Adviser Michael Flynn would meet with “Team Al-Assad” within 48 hours. She writes: "The substance of the text — that the Trump team started focusing on Syria right after the election — has been corroborated and tied to their discussions with Russia at least twice since then.”

"The substance of the text — that the Trump team started focusing on Syria right after the election — has been corroborated and tied to their discussions with Russia at least twice since then.” The identity of Wheeler's source is not yet public, but it may soon be revealed as the Mueller investigation continues. Wheeler is now a witness in the investigation.

Paul Manafort's locker

Paul Manafort's lawyers are arguing that an April 2017 off-the-record meeting between Justice Department prosecutors and four Associated Press reporters "was a potential conduit for improper leaks to the press about the probe that led to two criminal cases against the former Trump campaign chief," reports Politico.