house_feud_murder_effect

house_feud_murder_effect = {
	if = {
		limit = {
			has_bp1_dlc_trigger = yes
			exists = $VICTIM$.house.house_head
			exists = $MURDERER$.house.house_head
		}
		$VICTIM$ = { save_scope_as = house_feud_victim }
		$MURDERER$ = { save_scope_as = house_feud_attacker }
		scope:house_feud_victim = {
			save_ongoing_house_relation_effect = { TARGET = scope:house_feud_attacker }
		}
		# Notifications
		# Inform victim house that they have lost score
		if = {
			limit = {
				# Victim's House is targeted by killer's House
				scope:house_feud_victim = {
					house_has_feud_relation_with_trigger = { TARGET = scope:house_feud_attacker }
				}
			}
			scope:house_feud_attacker.house = {
				change_house_relation_feud_score_effect = {
					TARGET = scope:house_feud_victim.house
					REASON = kill
					VALUE = house_feud_medium_counter_value
				}
			}
			scope:relation ?= {
				if = {
					limit = {
						scope:house_feud_attacker.house = var:house_feud_house_1
					}
					set_variable = {
						name = house_feud_house_1_recent_kill
						value = scope:house_feud_victim
						months = 6
					}
				}
				else = {
					set_variable = {
						name = house_feud_house_2_recent_kill
						value = scope:house_feud_victim
						months = 6
					}
				}
			}
		}
		# Events
		# Fire Feud start event for victim house
		if = {
			limit = {
				scope:house_feud_victim.house.house_head ?= {
					NOT = {
						has_any_bad_relationship_with_character_trigger = { CHARACTER = scope:house_feud_victim }
					}
					valid_for_feud_events_with_target_trigger = { TARGET = scope:house_feud_attacker }
				}
			}
			scope:house_feud_attacker = { house_feud_save_head_and_attacker_effect = yes }
			scope:house_feud_victim.house.house_head = {
				random = {
					chance = 25
					modifier = {
						add = 25
						has_trait = vengeful
					}
					modifier = {
						add = -25
						has_trait = forgiving
					}
					modifier = {
						add = 25
						has_any_bad_relationship_with_character_trigger = { CHARACTER = scope:house_feud_attacker }
					}
					trigger_event = {
						id = bp1_house_feud.0005
						days = { 5 15 }
					}
				}
			}
		}
		# Fire Feud revenge event for killer house
		scope:house_feud_attacker.house = {
			if = {
				limit = {
					any_house_relation = {
						has_house_relation_level = feud
						any_relation_house = {
							NOT = { this = scope:house_feud_attacker.house }
							this = scope:house_feud_victim.house
						}
						OR = {
							var:house_feud_reason ?= flag:head_killed
							var:house_feud_reason ?= flag:head_skull_sent
							var:house_feud_reason ?= flag:family_killed
						}
						var:house_feud_attacker ?= scope:house_feud_victim
						NOT = { exists = var:feud_avenged }
					}
				}
				house_head = {
					trigger_event = { id = bp1_house_feud.7001 days = 15 }
				}
			}
		}
	}
}

As written in game/common/scripted_effects/03_bp1_scripted_effects.txt.