Back when police were vigorously pursuing suspects following the 2013 Boston Marathon bombings, a senior communications adviser and speechwriter with 2020 presidential candidate Bernie Sanders wrote, "Let's hope the Boston Marathon bomber is a white American" -- and then confidently doubled down hours later, in a separate piece entitled, "I still hope the bomber is a white American."

David Sirota, an investigative journalist and social media attack dog who has slammed Sanders' opponents in recent weeks, was formally brought into Sanders' campaign on Tuesday, along with a slew of other political veterans.

In his 2013 op-eds, published by Slate, Sirota attempted to argue that "double standards" in politics and law enforcement meant that a non-white perpetrator would lead to an unjust response.

The April 15, 2013, bombings, which killed three and injured dozens others, were perpetrated by Dzhokhar Tsarnaev and Tamerlan Tsarnaev. The Kyrgyz-American brothers invoked extremist Islamic beliefs and said American military actions had motivated them. Dzhokhar has been sentenced to death; Tamerlan was killed.

The "specific identity of the Boston Marathon bomber (or bombers) is not some minor detail -- it will almost certainly dictate what kind of governmental, political and societal response we see in the coming weeks," Sirota, who was Sanders' press secretary when he served in the House of Representatives, wrote.

He added: "That means regardless of your particular party affiliation, if you care about everything from stopping war to reducing the defense budget to protecting civil liberties to passing immigration reform, you should hope the bomber was a white domestic terrorist. Why? Because only in that case will privilege work to prevent the Boston attack from potentially undermining progress on those other issues."

After accusing the American government of mobilizing "a full-on war effort exclusively against the prospect of Islamic terrorism," despite the existence of other terror threats, Sirota continued with a discussion of white privilege.

"I still hope the bomber is a white American." — Bernie Sanders 2020 communications adviser David Sirota

"If recent history is any guide, if the bomber ends up being a white anti-government extremist, white privilege will likely mean the attack is portrayed as just an isolated incident -- one that has no bearing on any larger policy debates," Sirota said. "Put another way, white privilege will work to not only insulate whites from collective blame, but also to insulate the political debate from any fallout from the attack."

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Amid a fierce backlash on social media, Sirota largely restated his arguments in a follow-up piece and asserted that a "measured" response to the bombings would not be possible unless the attackers were white.

"The reason ... to hope that the bomber ends up being a white American is because the double standard may prevent an overreaction to the heinous attacks in Boston," Sirota wrote. "Indeed, if the bomber ends up being a white American, there's a decent chance we will not see a redux of the post-9/11 period when we (among other things) initiated reckless wars, passed privacy-trampling bills like the Patriot Act, overspent on the Pentagon and targeted wide swaths of the population for surveillance/warrantless wiretapping.

"By the way, you don't have to be a person of color or a political liberal to hope the bomber ends up being a white American," Sirota continued. "You just have to be among the groups of Americans who don't like stuff like pre-emptive wars, the Patriot Act, warrantless wiretapping, the drone war, an unsustainable Pentagon budget and a broken immigration system. By their own rhetoric, some of those groups must include many self-described conservatives -- after all, they purport to care about civil liberties and say they want to reduce government spending."

Neither Sirota nor Sanders' campaign responded to Fox News' request for comment.

Sirota has a history of no-holds-barred rhetoric, and was apparently using his skills on Sanders' behalf even before he was officially brought aboard the campaign on Tuesday.

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An analysis by The Atlantic found that Sirota apparently scrubbed his social media profiles, including more than 20,000 tweets, on Tuesday after the magazine asked him questions about his aggressive posts blasting Sanders' Democrat opponents -- without disclosing that he had any affiliation with Sanders' campaign. Sirota was, at the time, working as an "investigative journalist" for his website Capital & Main.

Sirota, according to The Atlantic, blamed an "autodeleter" for the missing tweets, and said he was taking care of a sick child and could not respond to inquiries on Tuesday.

Despite that purported inconvenience, Sirota "did post a photo on Twitter of himself bowling on Monday evening, wearing a turkey hat," The Atlantic noted.