A senior technical executive for the Electric Power Research Institute is also quoted as saying, "The breadth and depth of the attack was unprecedented." He said it "appears to be preparation for an act of war."

KQED’s Mina Kim speaks with Wall Street Journal reporter Rebecca Smith about the story and PG&E’s response to the attack:

Wellinghoff told the Journal that FERC believes taking out just a small number of substations could result in a near-total blackout around the U.S., and he said he's going public with his concerns due to fears that a bigger attack could be in the works.

The FBI told the Journal it did not believe a terrorist organization was involved. There have been no arrests in the case.

(By the way, for a final bit of intrigue, here's a Mercury News report about a man dressed in all black who was spotted near the property a month after the attack.)

Watch an interview with Wall Street Journal reporter Rebecca Smith:

And here's a Journal primer on the electrical grid system in the U.S.

And here is surveillance video from the night of the attack showing bullets hitting a fence at the substation, at around 2:50.

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San Jose Power Station Assault Called Terrorism