Although Michael Atkinson's name is not well known, it soon will be.  He's the Intelligence Community inspector general who fast-tracked the alleged "whistleblower" claim about Trump's July 25, 2019 phone call with Ukraine's President Zelensky, providing the basis for the House Impeachment proceedings.  In an interview with Sara Carter, Rep. Devin Nunes, the hero of the Russian hoax, let drop that House Republicans are investigating Atkinson's role in the Ukraine hoax:

[Atkinson] is under active investigation. I'm not gonna go any farther than that because you know obviously he has a chance to come in and prove his innocence, but my guess is Schiff, Atkinson they don't want that transcript out because it's very damaging.

Here are some facts explaining why Atkinson is an important figure in the Ukraine hoax underlying the sham-peachment:

It used to be that, to file a complaint with the ICIG, the complaining party had to have firsthand knowledge.  At some point between May 2018 and August 2019, the ICIG secretly removed that requirement.

That last date is significant, because the August 12, 2019 whistleblower letter that triggered the Ukraine frenzy states on its face that it is not based on firsthand knowledge: "In the course of my official duties, I have received information from multiple U.S. Government officials that the President of the United States ..."  In other words, "I don't know what the president has been doing, but other people have told me."

Worse, the evidence showed that the whistleblower originally filled out the old form, the one requiring firsthand knowledge.  It was only later that the new form suddenly appeared in connection with the complaint.  Thus, Devin Nunes explained,

So the form that the whistleblower filled out — he actually filled out the old form that said you had to have firsthand knowledge. The whistleblower readily admits he doesn't have firsthand knowledge. So conveniently the IG did this, claims that was always the case, claims it wasn't the law; I already told you, he's going to have more questions to answer," he said.

In an earlier interview with Matt Boyle, Nunes said Atkinson's testimony, which has yet to be released, showed him to be "either totally incompetent or part of the deep state, and he's got a lot of questions he needs to answer[.]"

If one assumes that Atkinson is not completely incompetent and then wonders why he would behave in such an underhanded way, his D.C. connections might help explain what was going on.  Back in 2016, before becoming ICIG, Atkinson was the senior counsel to the assistant attorney general of the National Security Division of the Department of Justice.  More simply, he was senior legal counsel to John Carlin.

Who is John Carlin?  Before Atkinson became his legal counsel, Carlin had been chief of staff to Robert Mueller, when the latter was FBI director.  When Carlin left that job, he became an assistant attorney general and head of the National Security Division.  In that capacity, Carlin was one of the last people to sign off on the FBI's Carter Page FISA warrant.  If nothing else, Washington, D.C. is an incestuous place; the people involved in both the Russian and Ukraine hoaxes all know each other...really, really well.

For a detailed overview of Atkinson's role, check out Sundance's post at The Conservative Treehouse.