Deputy Attorney General Rod Rosenstein, who appointed special counsel Robert Mueller to investigate Russian election meddling, had a few things to say about the way it started.

Starting with the Obama administration.

"The previous Administration chose not to publicize the full story about Russian computer hackers and social media trolls, and how they relate to a broader strategy to undermine America," he said.

Rosenstein punched back at critics during a speech at the Armenian Bar Association’s Public Servants Dinner in New York City on Thursday, where he defended the Department of Justice's handling of the investigation and his role in it.

"There was overwhelming evidence that Russian operatives hacked American computers and defrauded American citizens, and that is only the tip of the iceberg of a comprehensive Russian strategy to influence elections, promote social discord, and undermine America, just like they do in many other countries," he said.

But it wasn't for the DOJ to make an ultimate finding.

"I did pledge to do it right and take it to the appropriate conclusion. I did not promise to report all results to the public, because grand jury investigations are ex parte proceedings. It is not our job to render conclusive factual findings. We just decide whether it is appropriate to file criminal charges," he said.

The Justice Department came under fire from critics following the release of the 448-page Mueller report. A four-page summary by Attorney General William Barr that determined that while Russia had interfered in the 2016 presidential election, the Trump campaign did not collude with the effort.

[Barr: Mueller report makes 'clear' Russia meddled in 2016 election]

While Mueller said did not draw a conclusion about whether President Trump obstructed justice, saying the report "also does not exonerate him,” Barr and Rosenstein concluded there was not sufficient evidence to determine whether Trump did so.