Booth, you heard it here (though not here first, because Slate, the NYT and others have been at pains to deny it earlier). There is no knockout game. That fist you felt at the base of your neck was grape-fruit hail. The fact that an iPhone vid of the attack was later posted on YouTube, well, don't let that sway you.
And, certainly, it's never happened in DC. Or at least, not recently, and not five years ago. Perhaps in between, but what would that prove?
Phoebe Connolly was attacked on 11/15/2013 in Columbia Heights. It seems another woman was attacked the day also in Columbia Heights. Matt Yglesias was attacked 2.5 years ago off of North Capitol St. & New York Avenue which is right across from a large housing project (I think that area is called Old City). Where is the pattern Columbo? And I still do not see how this has in your mind has become a "5 year trend" when according to your own posts, there were no records of this happening 5 years ago. Hell as of 11/13/2013 the Yglesias attack was the only one in DC.