DETROIT -

Boston bombings suspects The push is on to get key information from a suspect in the Boston Marathon bombings, and investigators know they must work fast.

Read more: Federal charges filed for Boston bomb suspect

One of the most important aspects of the case is whether the two suspects acted alone.

Andy Arena, the former head of the FBI in Detroit, knows how important getting information from the suspect is in the hours after an attack.

"I think they want to know what caused this," said Arena. "Was the brother radicalized overseas, were they radicalized online?"

A similar situation played out with underwear bomber Umar Farouk Abdulmutallab in Detroit. One big difference is the accused Boston bomber is unable to speak. Instead, he's writing down answers.

"If he has time to think about it, you know, 'how do I couch my answer,' it's much better to have that back and forth with the person," said Arena.

The Boston bombings suspect was not read his Miranda rights immediately because agents had an urgent need to get critical information as soon as possible.

"The big thing here is the protection of society. Advising his rights to a counsel, really ... there obviously is a big enough exception to make sure that we don't have any other bombs lying around," said legal expert Todd Flood.

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