"The Professor," a central figure in the Robert Mueller investigation, seems to have disappeared.

Have you seen this man?

Courtesy of CNN:

Joseph Mifsud, the Maltese academic suspected of being a link between the Trump campaign and Russian officials, was once a regular on the foreign policy circuit, attending conferences the world over. 

Now, after being identified as a key figure in the US special counsel investigation into Russian influence over the 2016 US presidential election, Mifsud has gone to ground. 

Last Thursday he disappeared from the private university in Rome where he teaches. Repeated attempts to reach him since have been unsuccessful, though he appears to have read some messages from CNN. 

But more details are emerging of the background and contacts of the man who emerged last week as "the professor" in court filings relating to charges brought against former Trump aide George Papadopoulos. 

In the US affidavit, Papadopoulos claims Mifsued -- referred to as "Foreign Contact 1" -- told him in April 2016 that the Russians had "thousands of emails" relating to Hillary Clinton.

An associate also told CNN that he repeatedly bragged about how Moscow had "compromising material" on the Clinton campaign in spring 2016, contradicting Mifsud's assertion that he never talked about Russian "dirt" on the Democratic presidential bid.

I think Mueller needs to start offering to take these folks into protective custody, because once Putin knows who they are targeting he will not let them simply wander around loose.