The abstract noun "conspiracy" can be translated with the verb "plan." It can be stated clearly what this conspiracy was. Alternate translation: "how he planned to murder King Zechariah" or "and how he murdered King Zechariah" (See: [[rc://en/ta/man/translate/figs-explicit]])
This can be stated in active form. Alternate translation: "you can read about them in the book of the events of the kings of Israel" (See: [[rc://en/ta/man/translate/figs-activepassive]])