After unlocking the databank secret "Illuminati Dollar Bill" from the level, "Life or Death" Veiw this secret and press x to enlarge the picture. Read the letter that is now visible. this exact letter proves that the illuminati and the Masons are in fact connected (as according to the game). here it is.

"Enlightened Ones,

Please see the enclosed mockups for the new Us Dollar Bill.

As you can see, by applying the illuminati Red hexagram to the image, the All Seeing Eye of Horus oversees the other points on the hexagram. These points spell out the letters 'A-S-N-O-M' or 'MASON' when unscrambled as a tribute to our Free Mason brethren. This can also be seen when applying the Masonic Compass to the image.

Pretty snazzy eh? Adam Weishaupt would be proud. Let me know what you all think.

May Osiris smile upon us all.

Novus Ordo Seclorum
(New Age of Order)
-El"

There you have it. And it's also a link with Adam weishaupt because he was the founder of The Illuminati and joined The Freemasonry Lodge.