Sometime shortly before he was arrested Friday night hiding in a stranger’s boat, Dzhokhar Tsarnaev apparently tried to kill himself. Authorities say that he has a gunshot wound on his neck consistent with self-inflicted wounds. Today he is reportedly conscious and answering questions in writing. Hopefully he’s prepared to explain a few things.

The New York Times reports that the brothers told their carjacking victim that they were headed to New York. They evidently planned more attacks, which brings up an obvious question: Why did they tell the carjack victim where they were going, and why didn’t they just kill him? A possible answer: They didn’t kill him because they didn’t think he is an American. That didn’t stop them from using his ATM card though.

The brothers had amassed an arsenal of bombs and guns, including an M4 carbine rifle. Question: Where did the money for all that come from? Investigators don’t know yet, but that isn’t stopping Boston Mayor Tom “Mumbles” Menino from declaring that they acted alone. Even though the Russian government was worried enough about them to alert the FBI a couple of years ago. How visible did they have to be for the Russian government to notice them from the other side of the world? How bad is our immigration system, that they both still managed to obtain US citizenship? How craven are some of our politicians, that even after an attack that implicates the immigration system, they’re still pushing a sweeping “reform” that Congress hasn’t even read, and which would grant legal status to millions who have evaded the law for years? Those millions aren’t all terrorists, obviously, but we don’t know who they are. We didn’t know who the Tsarnaevs were, either, until last week.

How did they afford the weapons? How and where did they learn to build bombs and hand grenades, the latter they tossed out of the Mercedes they carjacked as police pursued them? Did they have some place outside Boston where they tested explosives, trained with their guns, and worked out their plan to bomb Boston and then other targets later? What role did their government-subsidized mosque play in all this? Are they a one-off, or the beginning of Chechen terrorism in the US? If the latter, why now? Is there any connection between this attack and, say, the ambiguous US position in the war in Syria — a war in which Chechens have surfaced working with al Qaeda to oust Assad? Authorities either don’t know or aren’t saying, probably some mix of both. If there really are other associates out there, keeping quiet may be best until they can be found, watched, and picked up.

The next few weeks are likely to be like last week in one respect: Conflicting information coming from unnamed sources about whether and how many other operatives may be out there. Were there just two, or up to fourteen in a sleeper cell, involved? So far, the answer is an ambiguous “yes.”