As I read about the early involvement of the secret service and in light of the later actions of the DoJ, I couldn't help but wonder if there was something to the signature of Swartz's actions that raised the Federal Government's level of interest.
To put it another way, how likely is it that that particular closet had been used for similar activities before? Is it more plausible that Swartz discovered the closet or that someone told him about it?
Hell, it was unlocked. The camera may have already been there and the Secret Service already involved. Swartz may have blundered into a honey hole and screwed up an ongoing investigation. That's the sort of thing which pisses cops off.
It's not easy to make sense of MIT's actions as naive responses to a one off event - disconnecting the laptop and alarming the closet would be more plausible as responses to a commercial crime. Putting in cameras and letting the crime continue just doesn't make sense in response to the sort of hacking which is traditional on the MIT campus (e.g. lockpicking). MIT went along until JSTOR took radical public action and data collection and observation by the Feds was no longer feasible.
If the proposed plea bargain required Swartz to cooperate with investigations of other hackers, neither side would have an interest in exposing it. The Feds for fear of tipping their hand, Swartz's survivors for remembrance of his legacy. All along I have had the feeling there is more to the tragedy than the press can get from their chairs.