First things first: ♦Understand Obama’s Surveillance Operation HERE.  ♦Michael Flynn wasn’t under a FISA (Title-1) HERE …. that’s the background.

The riddle of how the White House discovered the telephone call and subsequent content between Michael Flynn and Russian Ambassador Sergey Kislyak appears to have been solved. The FBI used a “Pen Register.”  There was no unmasking, and no warrant.

A pen register is a device/process which records the telephone numbers of outgoing calls.  Monitoring outgoing call numbers does not require a search warrant or FISA.

After the 2016 election Lt. Gen Flynn was given a government issued secure cell phone; a blackberry device for use.  However, with Flynn under a preexisting FBI investigation the phone numbers Flynn was calling in December ’16 and January ’17 were being monitored.

A review of prior testimony by former FBI Director James Comey [HERE]; prior testimony by former Deputy Director Andrew McCabe [Here]; and a cross-reference of recent releases of Flynn unmasking documents [Here] tells the full story.

In December of 2016 incoming National Security Advisor Michael Flynn was under a sketchy FBI Counterintelligence investigation for possible coordination with Russia.  According to recent documents and the Comey transcript, the Flynn investigation began in the summer of 2016; that investigation was ongoing in late December.

After President Obama initiated sanctions against Russia on December 29, 2016. The Obama administration was trying to figure out why Russia was not reacting.  According to James Comey testimony the intelligence community, writ large, was tasked to find out why Russia was not reacting more severely.  See Transcript:

Note:

…”And so we were all tasked to find out, do you have anything [redacted] that might reflect on this? That turned up these calls at the end of December, beginning of January.”

“do you have anything [redacted] that might reflect on this?”  Could pertain to the incoming administration, a person, or an intelligence capability.

However, to identify the “that“, we turn to the McCabe testimony (page 212):

…”in an effort to respond to the tasking from [REDACTED], and so the results of what we found were communicated to the Agency, who I think had the pen on that response.”

The individual or group initiating the task is redacted; however the redaction ends with the letter “f”, so it is most likely “redacted staff.”

Tasking from: NSC staff?  NCTC staff?  White House staff?

However, the other important facet is the “had the pen on that response.”  Meaning had the pen register responsibility on that response.

Pen Registers only monitor ‘outgoing‘ numbers.

It takes ‘trap and tracer’ authority to monitor the ‘incoming.’   Ambassador Kislyak was a foreign official whose surveillance would not require a pen register; however, a warrantless pen register would apply to Michael Flynn.  So the discovery of the contact reflects a review of Flynn’s calls; not just Kislyak (who can be monitored for any purpose).

The FBI discovers the contact via a pen register that was monitoring Flynn’s phone.  Then James Comey takes the information to DNI James Clapper.  Back to Comey transcript:

“And then I briefed it to the Director of National Intelligence, and Director Clapper asked me for copies [REDACTED] which I shared with him.”…

At this point it looks like James Comey uses the pen register to generate a non traditional intelligence product; perhaps a memo or rough draft of the transcript, or the pen register result itself; which, because of the content, contains Michael Flynn’s name.

Director Comey then shares with DNI Clapper.

Clapper then takes the document and uses it to brief President Obama.  This is how President Obama discovers the content of the call between Kislyak and Flynn:

The Clapper briefing of President Obama… likely happening prior to January 5th… using some non regular intelligence documentation…  is almost certainly the impetus for the unmasking request from President Obama’s Chief of Staff Denis McDonough which happened on January 5, 2017:

The January 5th unmasking request applies to a document about Flynn where Flynn’s name is unmasked.   That request is almost certainly the result of the White House receiving the official intelligence transcript of the Flynn-Kislyak call.  We know this because the non-traditional document that Comey gave to Clapper was not masked.

So the question becomes, what exactly was that ‘non-traditional’ intelligence document that Comey gave to Clapper to brief President Obama?

For that answer we go back to Andrew McCabe’s transcript as he described it (pg 213):

As you can see above McCabe describes the document as a “summary” of the call that “wasn’t an intelligence product”, and any unmasking would be unnecessary because Michael Flynn’s name within it was not masked.

That information flow is also why Lisa Page and Peter Strzok were saying “incidental collection” is the “incorrect narrative” in their text messages.  There was no unmasking because Flynn’s contact with Kislyak was not picked up as part of incidental collection, it was picked up because the FBI was using a pen registry to monitor all of Flynn’s contacts:

SUMMARY:  Flynn was under FBI investigation.  Per the IG report there was no FISA on Michael Flynn.  In the document generated by James Comey to share with DNI James Clapper,… to brief President Obama… Michael Flynn’s name was not masked.  The document was generated as a result of a pen register monitoring the outgoing contacts and phone numbers of Michael Flynn’s phone.

• Flynn’s call was the subject of a “pen registry”.
• Flynn’s device was government issued.
• Flynn’s “outgoing” calls monitored without warrant.
• Kislyak’s number was known.
• The pen registry identified the specific calls from Flynn to Kislyak.
• An “agency” provided the FBI with call content.
• Comey provided call content (w/ a document) to James Clapper.
• Clapper shared with White House during briefing.
• No unmasking, no warrant, no FISA.

That’s how the White House got the call without unmasking request.