The Third Murderer

by Tom Ingram

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I wasn’t aware of this when I did my analysis of Act 3 of Macbeth, but apparently there’s quite a bit of arguing going on about the identity of the Third Murderer. This is just a little baffling, because that’s quite possibly the least relevant detail in the whole play, but nonetheless I feel compelled to put in my two cents.

For those who don’t know, Macbeth hires two murderers to kill Banquo, who’s starting to grow suspicious. When the murderers set up their trap, a third murderer joins them out of nowhere, saying he was sent by Macbeth. The generally accepted reason for this is that Macbeth is so paranoid he can’t trust the hired help anymore. He needs a trusted assassin to keep his other assassins in check. That’s the third murderer’s purpose. His identity is completely irrelevant, and in any event it’s not terribly likely that he’s any of the named characters in the play. For my money, the third murderer is just a well-known professional that Macbeth believes he can trust.

Take note: Anyone who was at the banquet is not the third murderer. If your teacher tells you otherwise, your teacher is wrong. The entire purpose of the murder was to take place during the banquet, or just before it. It would not be possible for someone to kill Banquo and be back in time for the beginning of dinner, and nobody was mysteriously missing.

Along the same lines: Macbeth is not the third murderer. The whole point of hiring murderers in the first place was so Macbeth could distance himself from the killing and create an airtight alibi. If he physically takes part in the killings, it defeats the purpose of hiring people to do it. Not even Macbeth is that stupid. Also, Macbeth was in another place at the time of the killing. Macbeth as the third murderer is apparently a very popular view to take, but it’s also completely nonsensical.

Right off the bat, this rules out:

  • Macbeth
  • Lady Macbeth
  • Ross
  • Lennox

Other characters we can rule out without much thought:

  • Duncan (dead)
  • Malcolm (in England)
  • Donaldbain (in Ireland)
  • Banquo (the murder victim)
  • Fleance (onstage at the time of the murder)
  • Macduff’s son (we’d notice if it was a kid)
  • Siward and Young Siward (in England)
  • First and Second Murderers (onstage at the time of the murder)

This leaves a very small pool of suspects who were physically capable of committing the murder, going by the play’s cast list and disregarding servants and the like:

  • Lady Macduff
  • Macduff
  • Angus, Menteith, and Caithness
  • The Porter
  • Hecate
  • The Witches
  • Seyton

Let’s go through this list one by one.

Lady Macduff

I think we can safely disregard Lady Macduff. This was when Macduff left, so she was probably at home in her castle. The other murderers probably would have noticed if it was a woman helping them, and mediaeval society being what it is, they at least would have commented on it. I suppose it’s technically possible that she committed the murder, but it contradicts everything we know about her character.


At this point, Macduff is fleeing to England, so he has no time to lose. Besides, he and Banquo are allied against Macbeth.

Angus, Menteith, and Caithness

These three aren’t explicitly shown to be at the feast, but I think it’s safe to say they were there. They aren’t all that important to the story, but as high-ranking thanes their absence from the feast would have been noticed. From what we know about them, they’re morally upstanding, but none too intelligent, leaders. They help lead the army against Dunsinane at the end. None of them are Macbeth’s cronies.

The Porter

The Porter is an inept comic relief character. I don’t think we need to seriously consider the possibility that he’s the murderer (and besides, he would have to be at the castle manning the gate).

Hecate/The Witches

It’s entirely possible that one of them is the murderer, using their powers to disguise themselves. They would be willing to help him, too, to further him along his road to ruin. There’s nothing in the play that suggests that one of them is the third murderer, but the possibility is open.


This is the guy who does Macbeth’s dirty work. If you absolutely insist that the third murderer be a named character, Seyton is the one I’d bet on.