He's known as The Revolutionary, and he's hell-bent on creating a new world order, starting with Colombia. You'll visit Hitman 2's Colombian level to try and lay waste to his plans, and you have until December 30 to make him disappear quietly. Or not so quietly, if you prefer.
The intel you've got—outlined in the video above—is that Murillo is a paranoid man, a narcissist and a pathological liar. He also has...hint, hint...a drinking habit.
He seems to have several possible spawn points, giving you lots of options for taking him out. Just make sure you play the Colombia map in the regular game first to get a feel for its secrets—remember, you only get one shot at killing him.