Above, my screen shot of The Washington Post's website Saturday night, December 22nd, 2012, completely surrounded by the marketing efforts of a group that calls itself "Mayors Against Illegal Guns Action Fund." Nope, I'd never heard of them before, either. They probably don't call what they're doing above capitalizing on a tragedy, but rather taking advantage of a crisis. And we all know how Obama supporters hate to waste a crisis. But it's exactly what it looks like. An anti-gun only approach won't sway the majority of this country or Congress, but they don't seem interested in multi-prong solutions, only guns, guns, guns.
The Center for Responsive Politics seems to have about the most recent information on the group, such as it is, though I think that the FEC info might just be for sometime short of Election Day.
Just so you know, these are not just activists of the sort that every community has, but rather the sort that actually host President Obama fundraisers -with him there- instead of various celebrity surrogates.