A person is guilty of manslaughter in the first degree when:
1. With intent to cause serious physical injury to another person, he causes the death of such person or of a third person; or
2. With intent to cause the death of another person, he causes the death of such person or of a third person under circumstances which do not constitute murder because he acts under the influence of extreme emotional disturbance, as defined in paragraph (a) of subdivision one of section 125.25. The fact that homicide was committed under the influence of extreme emotional disturbance constitutes a mitigating circumstance reducing murder to manslaughter in the first degree and need not be proved in any prosecution initiated under this subdivision; or
4. Being eighteen years old or more and with intent to cause physical injury to a person less than eleven years old, the defendant recklessly engages in conduct which creates a grave risk of serious physical injury to such person and thereby causes the death of such person.
Manslaughter in the first degree is a class B felony.