(a) A person is guilty of assault in the first degree when: (1) With intent to cause serious physical injury to another person, he causes such injury to such person or to a third person by means of a deadly weapon or a dangerous instrument; or (2) with intent to disfigure another person seriously and permanently, or to destroy, amputate or disable permanently a member or organ of his body, he causes such injury to such person or to a third person; or (3) under circumstances evincing an extreme indifference to human life he recklessly engages in conduct which creates a risk of death to another person, and thereby causes serious physical injury to another person; or (4) with intent to cause serious physical injury to another person and while aided by two or more other persons actually present, he causes such injury to such person or to a third person; or (5) with intent to cause physical injury to another person, he causes such injury to such person or to a third person by means of the discharge of a firearm.
(b) Assault in the first degree is a class B felony provided (1) any person found guilty under subdivision (1) of subsection (a) shall be sentenced to a term of imprisonment of which five years of the sentence imposed may not be suspended or reduced by the court and (2) any person found guilty under subsection (a) shall be sentenced to a term of imprisonment of which ten years of the sentence imposed may not be suspended or reduced by the court if the victim of the offense is a person under ten years of age or if the victim of the offense is a witness, as defined in section 53a-146 , and the actor knew the victim was a witness.