9th of Av Destruction By Nebuzaradan The Butcher

9th of Av Destruction of the Beit HaMikdash was preceded by the mass murdering of Jews in Jerusalem. Nebuzaradan the butcher entered Jerusalem on the 7th of Av and began murdering Jews by the tens of thousands to avenge the blood of the prophet Zechariah who was murdered by the Jewish people that didn't like being rebuked for their sins. But after Nebuzaradan the murderer finished killing millions of Jews in Jerusalem, he realized that HaShem would avenge their blood, just like the blood of Zechariah.

"And in the fifth month, on the seventh of the month (that was the nineteenth year of Nebuchadnezzar king of Babylonia) Nebuzaradan, chief executioner, servant of the king of Babylonia, came to Jerusalem. And he burnt the house of the Lord and the king's palace, and all the houses of Jerusalem and all the houses of the dignitaries he burnt with fire. The entire army of the Chaldeans that was [with] the chief executioner demolished the walls of Jerusalem around. And Nebuzaradan the chief executioner exiled the remnant of the people who remained in the city, and the defectors who defected to the king of Babylonia, and the rest of the populace." Melachim II (II Kings) 25:8-11