Two of the three big figures from 2004's Orange Revolution have factored in the latest political upheaval: Viktor Yanukovych was ousted last month as president, and Yulia Tymoshenko was released from jail; she was serving a sentence that some saw as politically motivated.

Viktor Yushchenko, though, has hardly been heard from. In December, he and two other former presidents expressed solidarity with the protesters and called for both sides to refrain from violence. Otherwise, he's largely been quiet.

But his story in 2004 drew plenty of attention.

It sounded like a spy novel: A Ukrainian opposition candidate falls mysteriously ill, his face disfigured by a blotch of lesions. He has severe abdominal and back pain, and the left side of his face is paralyzed.

Yushchenko said he was poisoned. Opponents said maybe it was bad sushi and booze.

Austrian doctors said it was dioxin -- possibly placed deliberately in his food.

That announcement came on Dec. 11, 2004, just a few weeks after Yushchenko was beaten by Yanukovych in a soon-to-be-overturned runoff vote for the Ukrainian presidency. The new vote put Yushchenko in the presidency.

(That, of course, wasn't the end of Yanukovych's career: He was elected as president in 2010 -- and then was ousted by protesters last month. Check out our Ukraine glossary for more on 2004's Orange Revolution.)

But back to the potential poisoning. The Post's Peter Finn wrote in 2004:

Arnold Schecter, a dioxin expert at the University of Texas School of Public Health at Southwestern Medical Center in Dallas, said dioxins can be highly effective poison in people who are sensitive to their effects. If Yushchenko was deliberately given dioxin, it was done by someone who "was very clever and very knowledgeable," Schecter said.
"If someone put a drop of pure dioxin in his food, he wouldn't taste it, he wouldn't see it and a few days later he'd start to get sick," Schecter said.
"If you are trying to kill someone quickly, it's not the way to go," he said. "But if you want to disable someone and want to do it subtly and have it happen days or weeks or months after you have contact with someone, this can do it," Schecter said. "Plus there are very few labs in the world that can accurately detect dioxin in the blood."

How the poison got into his system was never uncovered, and his face still bears the scars.