Dan Rudolph, posting on the Oni Central forum, pointed out a MacGamer's Ledge article on the subject. Alex's parting with Bungie was entirely amicable and Matt had this to say to MGL:

He was one of the artists on the team, but he was so deeply involved for so long that calling him just an artist doesn't seem to do him justice. He did a lot of character design, storyboarded cutscenes, designed the cool particle effects that are in Oni now, created textures...he was just all over the place.

In addition to his work on Oni, Alex was extremely supportive of the Bungie fan community. He will be missed, but we wish him luck at his new job.

In other not-very-related news, Matt confirmed on Oni Central's forum that blood has been taken out of the game.