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 Times piece 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."

The new details also shed some light on the mysterious appearance of female DNA on the bomb fragments. Authorities warned at the time that the DNA could've made its way onto the bomb in a number of ways, many of which would not constitute conspiring in the bombing. Tamerlan Tsarnaev's wife, Katherine Russell, was immediately suspected, since she was living with her late husband during the planning stages of the attack. However, according to the Times's sources, the DNA does not belong to Katherine Russell. Nevertheless, she's recently stopped cooperating with authorities.

That's all we've got for now, though. The investigation isn't exactly becoming any simpler. We learned on Wednesday that police arrested three new suspects in the Boston bombing case — two students from Kazakstan and one American — under suspicion that they helped Dzhokhar after the attack. The evidence against them is significant, but that still doesn't explain everything. For that, we'll have to wait. Meanwhile, the case building against Katherine Russell is worth watching. Even if it was not her DNA on the bomb fragments, it's hard to understand how she never knew anything was going on. Of course, some husbands are good at hiding things.