So it seems reasonable to ask: was there something in the Bible that inspired the attack?

Of course it's hard to say, but there is plenty in the Bible that might encourage similar behavior.

Take his nakedness, for example. God seems to like his prophets to run around naked. Here are God's instructions to Isaiah.
At the same time spake the LORD ... saying, Go and loose the sackcloth from off thy loins, and put off thy shoe from thy foot. And he did so, walking naked and barefoot. And the LORD said, Like as my servant Isaiah hath walked naked and barefoot three years for a sign and wonder. Isaiah 20:2-3
God told Isaiah to walk around naked for three years as a sign and and wonder. Maybe Eugene was just trying to do likewise.