This was contributed to Cindy Smith:

I believe you're referring to Zechariah (9 letters). Jesus is speaking in [Luke 11:49-51]:

Therefore, the wisdom of God said, 'I will send to them prophets and apostles; some of them they will kill and persecute' in order that this generation might be charged with the blood of all the prophets shed since the foundation of the world, from the blood of Abel to the blood of Zechariah who died between the altar and the temple building. Yes, I tell you, this generation will be charged with their blood!

Abel was the first person ever murdered, according to [Genesis 4:8], while Zechariah is the last person murdered in the Old Testament, according to [2 Chronicles 24:20-22].