Former Deputy Attorney General Rod Rosenstein hit back at ex-FBI director James Comey for questioning his conduct after the release of the Mueller report, in a speech to the Greater Baltimore Committee Monday.

"The former director is a partisan pundit, selling books and earning speaking fees while speculating about the strength of my character and the fate of my immortal soul. That is disappointing. Speculating about souls is not a job for police and prosecutors. Generally, we base our opinions on eyewitness testimony."

Context: In an opinion piece for the New York Times last week, Comey asked how Rosenstein could "give a speech quoting the president on the importance of the rule of law" following the release of Mueller's report, which he said detailed President Trump’s determined efforts to obstruct justice.

Why it matters: Rosenstein wrote the letter that Trump used as a basis to fire Comey in May 2017, as the Russia investigation intensified. Comey's firing was a key aspect of special counsel Robert Mueller’s investigation into whether Trump obstructed justice. Rosenstein appointed Mueller to lead the investigation.

In his first public speech since stepping down as deputy attorney general, Rosenstein told the GBC it was Comey's handling of former Secretary of State Hillary Clinton's email investigation in 2016 that was a defining professional error. He expressed some sympathy for the former FBI director but said, "There are bright lines that should never be crossed."

"If I had been the decision-maker, the removal would have been handled very differently, with far more respect and far less drama, so I do not blame the former director for being angry."

Go deeper: Timeline: Every big move in the Mueller investigation