Whodunnit? The Complete Solution! (FalcoPhiles)

Whodunnit?

So you're tearing your hair out trying to find the murderer? Don't panic, I'll take you through each step of the way to solving the logic problem.

Here is the problem (you'll need to refer to this):

Julius has been found dead in the triclinium, his Falernean poisoned. Four men seated on a divan and two chairs in front of a hanging ceremonial shield discussed the foul deed. Their names are Marcus, Gaius, Tiberius and Lucius. The are, not necessarily respectively, a Senator, Rhetorician, Centurion and Priest.

The slave pours a glass of Falernean each for Tiberius and Gaius.
The hanging shield is reflective and the Senator sees the slave leave and close the door. He turns to speak to Lucius, next to him.
Neither Marcus nor Gaius has any sisters.
The Rhetorician is a teetotaller.
Marcus, who is sitting on one of the chairs, is the Centurion's brother-in-law. The Rhetorician is sitting on Marcus' left.

Suddenly a hand moves stealthily to put something in Tiberius' Falernean. It is the murderer. No one has left his seat and no one else is in the room. What is the occupation of each man, where is he sitting and who is the murderer?

The Crime Scene. A graphics enabled browser is recommended for this game.
The Crime Scene

Now, here is the solution:

Read ALL of the clues through at least once.

Work backwards through the clues to mine out all the information. Before you start noting things down, draw out a table like the one below:

Position	Person	Occupation
A
B
C
D

From Clue #5

Marcus is in a chair, so he is in either position A or D (the two chairs).
The Centurion is Marcus' brother-in-law, so Marcus is NOT the Centurion.
Either the Centurion or Marcus must have a sister (if one is the brother-in-law of the other).
The Rhetorician is on Marcus' LEFT. Look at the diagram of the room - Marcus must be in chair A to have somebody on his LEFT. [Fill in Marcus next to position A in your table]
Therefore the Rhetorician must be in position B. [Fill in Rhetorician next to position B in your table]
Marcus is NOT the Rhetoric.

From Clue #4

The Rhetorician does not drink alcohol. He is teetotal.

From Clue #3

Neither Marcus nor Gaius has a sister, so referring back to Step 3(c) (about brothers-in-law), it must be the Centurion who has a sister.
Therefore, Gaius can not be the Centurion (because Gaius hasn't got a sister, but the Centurion has).

From Clue #2

If the Senator is in line with the shield to see the reflection of the door, he must be on the divan, in position B or C.
The Rhetorician is in B (because he is on Marcus' left), so the Senator must be in C. [Write this in your table]
Lucius is NEXT to the Senator - therefore Lucius is NOT the Senator.
Lucius must be in either position B or D.
Marcus (who is in position A) can not be the Senator.

From Clue #1

Falernean is a type of Roman wine, so Tiberius and Gaius are NOT teetotal!
Therefore, neither Tiberius nor Gaius are the Rhetorician (who is teetotal).

We now put all the clues together to read between the lines.

If Marcus, Tiberius and Gaius are NOT the Rhetorician (Marcus is sitting in the wrong place and Tiberius and Gaius are not teetotal), then it MUST be Lucius. Therefore, Lucius is the Rhetorician and sits in position B (because the Rhetorician sits on Marcus' left). [Write this in your table]
If B is the Rhetorician, C is the Senator (because the Senator must also be sitting on the divan) and A is Marcus - who is NOT the Centurion (because the Centurion is Marcus' brother-in-law) - then the Centurion MUST be D. [Write this in your table]
Marcus MUST be the Priest, because it is the only job left over. [Write this in your table]
If Gaius doesn't have a sister, then he is NOT the Centurion (who does have a sister). Therefore Gaius MUST be the Senator in position C (because Marcus is A and Lucius is B). [Write this in your table]
Therefore, the Centurion in position D has to be Tiberius. [Write this in your table]

We now have the table filled in like this:

Position	Person	Occupation
A	Marcus	Priest
B	Lucius	Rhetorician
C	Gaius	Senator
D	Tiberius	Centurion

So who is the murderer?
Referring to the text that comes after the clues, it says nobody left their seat when the second murder attempt took place. Therefore, they MUST have been NEXT to the victim (who was Tiberius, ruling him out as the murderer - we take it for granted that it's not a suicide attempt of a man with a guilty conscience!), so it HAS to be Gaius (in position C) the sneaky, loathsome Senator!