Mir Hussein Mousavi and Mehdi Karroubi, two of the most visible leaders of Iran's Green Movement and recent presidential candidates, and their wives appear to have been arrested. Why so tentative? A couple reasons: 1) They have been under house arrest from time to time almost since the protests of the Summer of 2009 2) No official government source says so--in fact a few insist they are just under house arrest 3) Sources close to them claim they have been arrested and various other sources appear to have unofficially confirmed that they are in Heshmatiyeh prison in Tehran.
There are a number of reasons for this development, and a few different possibilities for how this might turn out. Like most things in Iran, anyone who tells you they know exactly what is going on is a fool or they are lying. Let's take a closer look.