Several suspects in killing of Mostafa Ahmadi Roshan arrested

From the horse's mouth (or from the general area of it):

Iran has arrested a number of people in connection with the assassination of the academic, Majlis Speaker Ali Larijani told Al-Alam News Network on Monday.

Of course, prison walls, even in Tehran, are a scant protection from the Elders' information machine. So, for your viewing pleasure, here are the pictures of the suspects:

The arrested are signing their confessions currently.