Story at The Japan Times.
I can certainly understand why he did it. Must be demoralizing to spend hours chasing a Chinese fishing boat which has rammed two coast guard vessels . . . only to see the Japanese government let the perp walk.
UPDATE (Nov 10/2010): Thought so.
"He was aboard a patrol boat for many years, and I suppose he might have felt righteous indignation about the fact that his colleagues' clash with a Chinese ship at the risk of their lives was hidden from the eyes of the public," a JCG official said.