After killing Al Muaiam and returning to the real world, listen to the conversation about how they going to kill you. Turn on your Eagle Vision and look at the floor. There are some mixed up letters on both sides of the Amnius. You should see on the side closest to the main door:

M O R Y M N O E S
E N C E O L C H T
H O N B T L O T C
T D E O S A T O A
P E D S N L S T F
L D D U O O E T E
E A I E I R I N T
H S H K T T K E R
T U A A A N S S A

To decode this, start reading at the bottom right hand corner to the top right hand corner, so you will start at "A" and stop at "S". It will spell a real word. Do this for all of the columns and it will read:

ARTEFACTS SENT TO THE SKIES TO CONTROL ALL NATIONS TO MAKE US OBEY A HIDDEN CRUSADE DO NOT HELP THEM

Next, do the same thing to the mixed letters on the other side of the Amnius:

A
D R H
O O D T M
W H B I T D O
E U S Y S I N S E
A R O O M R E A Y N R
I S E Y T N I D L M I D E
T W I H W Y I E A U D A Y H T

It will spell out: THEY DRAINED MY SOUL AND MADE IT THEIRS I DRAINED MY BODY TO SHOW YOU WHERE I SAW IT.