>That was the Oklahoma bombing, right?

Yes, the Oklahoma City bombing of a US government building.

>It is very sad when this kind of thing happens - anywhere in the world. Can you remind me what his apparent or claimed motives where? I didn't follow this case very closely.

He felt like the US government had too much power, stemming from a conflict in Waco, Texas, where a government agency (ATF - Alcohol, Tobacco, and Firearms) tried to forcibly enter a compound run by a religious nut with a penchant for weapons. He choose the anniversary of that Waco disaster (April 19th) to blow up the federal building in Oklahoma City.