Here is the text of the definition of manslaughter in the Kentucky penal code:

"(1) A person is guilty of manslaughter in the first degree when: (a) With intent to cause serious physical injury to another person, he causes the death of such person or of a third person; (b) 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 subsection (1)(a) of KRS 507.020; or (c) Through circumstances not otherwise constituting the offense of murder, he or she intentionally abuses another person or knowingly permits another person of whom he or she has actual custody to be abused and thereby causes death to a person twelve (12) years of age or less, or who is physically helpless or mentally helpless."

"Intent" is a clear component of every one of those sections. And intent must be provable in order to convict someone of it. To charge the cops with manslaughter means you believe the police went to that house intending to cause harm wot another person and not just to execute a warrant.