At the moment three persons have been linked to PEGASUS:

PEGASUS is all about the building at the back alley of 3518 REAR 11th Street NW in DC:

Google img, streetview.

Images from dcocto in april 2015: top, front, right, back, left

Due to the cadastral situation (osm) it has been referred to as 3516 REAR and 3518 as well as 3518 REAR.

Video of voat user site visit ~dec 15: url, original

A timeline of how PEGASUS evolved:

May 27 2014 John Kreher registers HERECOMESYOURMANLLC in Delaware (img, url, arch).

May 27 2014 John Kreher and Alefantis register a branch under the same name in DC (img, url, arch).

Jun 16 2014 Alefantis registers CASTELLUM ACHILLES LLC (img, url, arch).

Jul 25 2014 CASTELLUM ACHILLES LLC buys 3518 REAR 11TH Street NW in DC (img, url (open twice)).

Nov 15 2014 Alefantis posts image on Instagram of John Kreher and another person looking at hole in floor img, arch

Dec 24 2014 Alefantis posts image of two guys breaking up the floor and digging in the building img, arch

Jan 6 2015 Alefantis gets building permits for the building (img, url) and applies for one that is ultimately cancelled on Feb 8 2016 (img, url)

Oct 7 2015 More building permits (img, url).

Jun 30 2016 More building permits (img, url).

Jul 28 2016 Alefantis adds a MUSEUM named PEGASUS to google maps (img, img, img, link(link defunct, see Dec 18 2016 entry), google mapmaker (Note: you need to login to see the edits, also note that when you login your username is 'Anonymous_1234')).

Oct 2016 Alefantis reviews the MUSEUM 5 stars ('2 months ago' on Dec 12) (img).

Oct 4/5 2016 Valerie Wiseman posts image on Instagram showing a mattress in the building alley (img, arch, streetview).

Oct 4/5 2016 An image showing the view from a window in the building at the alley side (img, arch, streetview).

Oct 4/5 2016 An image showing a 'Dick boyz' tag in the alley (img, arch, streetview).

Oct 8 2016 An image showing the view from a window in the building at the playground side, comment 'Peeking' (img, arch, streetview).

Oct 11 2016 A screenshot showing she uses the 'Dick boyz' tag as background on her phone ((img, arch)).

Oct 17 2016 An image showing her cat with PEGASUS wings (img, arch)

Nov 1 2016 Valerie Wiseman updates her website listing PEGASUS (and Comet and Buck's) as active projects (url, archive) (date approx, from pizza.png foursquare timestamp src, time)

Nov 7 2016 An image of a Hillary-photobooth-picture at the 10y Comet Ping Pong party (img, archive).

Nov 7 2016 An image showing a 'Fuck swag' tag on the garage next to the building, comment 'Amirite?' (img, archive, streetview).

Dec 13 2016 Valerie Wiseman posts strange ambiguous statement about pizzagate (url, archive):

How do I use words to describe the past few weeks? Careless words and reckless actions got us here, but also so did silence and indecision. The gray area doesn't exist anymore, but everything is also a little gray, right? Can I 'give it a minute' if there aren't any [is this how I finally learn to be present]? Let's eat pizza and drink beer and make some art with all this shit. Comet, you are so much more than your google.

*** ADDED DEC 19 04:30 ***

Dec 18 2016 ~20:30 The PEGASUS marker was removed from google maps: see img and img and img

*** ADDED DEC 19 08:00 *** More pictures, found in jimmycomet instagram caches (1: url img arc, 2: url img arc):

May 31 2015 Alefantis posts image of construction worker looking through a window at the property img "Back to work."

Jun 2016 Another construction worker img "here we go again.... #destruction #amos"

Jun 2016 Construction blueprint img "back at it. #floor mfproper joewills thoughts"

Sep 2016 Another construction worker, overlooking the playground from the roof img "ugh. #backtowork #amos"

Note: amos, src. Mfproper aka Matt Proper aka Matthew F Proper and joewills aka Joseph Corbin Wills seem to be involved in PEGASUS as well, more in comments and later.

Continued below/here