Whoever placed these devices is/are presumably still lying low someplace in New England right now and has demonstrated a willingness to murder/maim innocent people and could be planning to do so again.

Frankly "due process" does not seem that important right now (as soon somebody is formally detained or accused, agree with you 100% on due process), but what is most important at this moment is getting credible leads/clues into the hands of law enforcement as quickly as possible.

The people poring over photographs are doing just that