I know that you're being facetious, but they won't go after "bombs" here.
I'm not passing judgment on "inside job" or not, but the thing that they will go after has already been hinted at: being able to shut down cell networks and communications. My prediction will be that these devices will be found to have had cell-triggers, and the govt will push for being able to place local black-outs on all communication devices at any events/gatherings.
Since there has been little "official" hints at a culprit, I doubt that anyone will ever be fingered in these bombings. Without an official culprit, the conspiracy theorists will be able to run wild with speculation, and further alienate those who look for reason and meaning from the mainstream of the population.
For real, this had to be the Lizardpeople using zero-point energy weapons to vaporize the organic material near the laser beams with the purpose of regulating marathons because they don't want sporting competitions where some people are able to win at the expense of others. Duh.