As more details of Dzhokhar Tsarnaev's bedside interrogation leak out, we learned on Thursday night that the brothers originally planned a Fourth of July attack but built their bomb too quickly, leading them to consider another target. An information-rich and just published New York Time spiece explains a series of new details about the planning of the attacks. The paper's unnamed sources say that Dzhokhar revealed two days after the attack that he and his brother "considered suicide attacks and striking on the Fourth of July."
In fact, the reason that they didn't stage an attack on July 4 was because the pressure cooker bombs were so easy to make. The Times reports, "The brothers finished building the bombs in Tamerlan's apartment in Cambridge, Mass., faster than they anticipated, and so decided to accelerate their attack to the Boston Marathon on April 15, Patriots' Day in Massachusetts, from July."