I almost suggested what Losilmer just said, but then I would want to change "made" to "kept making".
In my mind, the criminal had everyone kneel down first, with the intention that they should continuing kneeling until further notice, then as he robbed the bank, he may have "spot checked" whether or not they were still kneeling down.
Losilmer's sentence means that the criminal was robbing the bank and then made everyone kneel down, perhaps more than once during the robbery.
The original sentence is more ambiguous but says practically the same thing as Losilmer's sentence. Removing a comma or two does not help.
The commas improve readability. The phrase in question fits more naturally after "the criminal" than before it, but in that position the comma is needed so as not to suggest that the criminal was only a criminal while robbing the bank.