I heard a low aircraft fly over, and I looked on adsbexchange and there was a strange aircraft, the type was listed as "BER2" and the tail number was "RF-31121" which seems to be an aircraft that belongs to what essentially seems to be the Russian version of FEMA based on a google search. But they seem to be flying around the beltway and then over DC itself, it's strange. It doesn't seem to have adsb, because on adsbexchange it says the source is MLAT. I didn't hear anything on the approach frequencies on liveatc (though I'm not too sure which frequency i'd even need to listen to). I suppose it must be something related to the coronavirus. Anyone have any idea what it might be doing?