I've written a fair amount about package thieves before -- in northern Columbia Heights, the area around 14th and Otis to Spring, there seem to be some thieves afoot, taking packages from people's stoops.
One victim seems to have gotten fed up, as there's a poster up around the area with a picture of an alleged thief. I spotted this one at 14th and Spring and friends saw some farther south too.
Maybe they put up a security camera or something -- I'm not sure as there's no other contact info. I hope it works out, I know a number of folks (me included) have been victims.
And make sure you call the police if your package was stolen, even if you don't think they can catch the crook. At least the police will know more about the patterns and similarities of the crimes. In fact, MPD has caught some in the past.