What specific crime do you believe they committed, and why?
See Bernanke's take: http://www.usatoday.com/story/news/politics/2015/10/04/ben-b....
It seems like the right person to jail in this case is the person who lied to the bank.
But those loans also shouldn't have been granted, which was the bank's responsibility. Most of them should have been caught during underwriting and verification. What, exactly, were they doing?
This is a deception or failure on both parts.