§ 160.15  Robbery in the first degree.
    A  person  is  guilty  of robbery in the first degree when he
forcibly  steals  property  and  when,  in  the  course  of   the
commission  of  the crime or of immediate flight therefrom, he or
another participant in the crime:
    1.  Causes serious physical injury to any person who is not a
participant in the crime; or
    2.  Is armed with a deadly weapon; or
    3.   Uses  or  threatens  the  immediate  use  of a dangerous
instrument; or
    4.   Displays  what  appears to be a pistol, revolver, rifle,
shotgun, machine  gun  or  other  firearm;  except  that  in  any
prosecution  under this subdivision, it is an affirmative defense
that such pistol, revolver, rifle, shotgun, machine gun or  other
firearm  was  not  a  loaded  weapon  from  which a shot, readily
capable of producing death  or  other  serious  physical  injury,
could be discharged.  Nothing contained in this subdivision shall
constitute  a  defense  to  a  prosecution  for,  or  preclude  a
conviction of, robbery in the second degree, robbery in the third
degree or any other crime.
    Robbery in the first degree is a class B felony.