Details to follow…

Update via TPM:

While investigators have not yet publicly revealed the alleged conduct of the three new suspects arrested in connection with the Boston Marathon bombings, they are focusing on whether the three aided accused bomber Dzhokhar Tsarnaev, according to NBC News’ Pete Williams.

Williams reported Wednesday on-air that the new suspects in the case have been under FBI surveillance for more than a week. “The question is whether they helped to take things out of Dzhokhar Tsarnaev’s dorm room after the bombing,” Williams said, according to a rush transcript. “Now, no one is saying at this point that they have knowledge of the bombing in advance. That’s been the big question. We’ll probably learn more about the answer to that question later today when these charges are made public.”

A CBS News producer tweeted that the network confirmed “3 suspects were arrested for harboring/aiding the bombing suspects after the fact. These will be federal charges.”