We know the "what", the "when", the "where" and the "how" rather precisely.
As evidence filters in about the Boston Marathon bombing, the big question is "who?" (The "why" inside the head of the sick fuck who did it hardly matters.)
Was this a 9-11 like international terrorist attack intended to punish the United States? Was it an act of domestic terrorism probably with some far right cause? Was it the act of some derranged individual with no greater agenda than to achieve infamy (not unlike the Aurora theater shooting)?
No one has claimed responsibility. The Pakistani Taliban issued a statement denying a connection. The bombs themselves were not packed with sharpnel to produce any more damage than they did. Statements that there were more than two bombs in the vicinity or that a fire at the JFK library were related have proved to be unfounded. In short, this incident was of a scale that could have been orchestrated by a single individual acting alone.
The twenty-year old Saudi Arabian ESL student detained at the scene whose shared rental condo is being searched by authorities appears at first glance to have been nothing but an innocent bystander.
It is hard to see why any terrorist with a political agenda would let the incident come without a claim of responsibility (unless the terrorist was killed accidentally by the blast denying him or her the opportunity to spout an agenda later). One could also imagine a terrorist, or perhaps a mere prankster who underestimated the consequences, seeing the carnage and having a change of heart about whether carrying out this act should be used to advance a cause.
The marathon route was swept by police for bombs that morning and there were countless photographs and videos taken by people interested in capturing the race that morning and there are tens of thousands of potential witnesses. But, in the critical first twenty hours after the bombing there appear to be no solid leads yet. Solving this case may involve a long, tedious slog of reconstructing from videos and photographs and tens of thousands of witnesses and bomb remnants how the bombs were put where they exploded, how they were detonated, and who put them there in a narrow window of time after a morning sweep of the route and before the explosion.
We know an eight year old boy and two unidentified people died and that at least seventeen others had critical injuries (including two relatives of the boy who was killed) with numerous people having legs amputated as a result of the blast (including two brothers who each lost part of a leg). At least 176 people were injured. It is possible that additional people may yet die from their injuries although the fact that the critically injured all seem to have lived though the day is encouraging.
Cell phone service was immediately shut down near the blast area to prevent phone activated detonations (a lesson learned, although apparently unnecessary in this case, from Iraq). A no fly zone was imposed in Boston and public transit was temporarily halted in the city. Searches on transit and passenger rail and heightened security citywide persist today.
Investigators are rumored to be slightly favoring the possibility of domestic terrorism, in part, because the bombing took place on Patriot's Day and the national deadline for filing tax returns, and in part, perhaps because of the theme of this year's race "26 for 26", a reference to the Newtown Connecticut Massacre at Sandy Hook Elementary School that has spurred gun control efforts nationwide. Thus, anti-tax and anti-gun control motives would have spurred an act of a domestic terrorist.
The fact that the name of the two other dead have not been released yet could be for a pedestrian reasons - a difficulty in identifying a victim or an inability to locate next of kin, or could suggest that authorities suspect that one or both of the individuals could have been perpetrators.