(CBS News) BEIJING -- Secretary of State Hillary Clinton was en route to China Tuesday for high-level economic and strategic talks.
But there's something neither Clinton nor the Chinese want to talk about - a Chinese activist believed to be in the hands of U.S. diplomats.
The fate of a single man -- human rights activist Chen Guangcheng -- threatens the already-tense relationship between the U.S. and China.
After a dramatic escape from house arrest, the blind, self-taught lawyer is probably hiding inside the U.S. Embassy in Beijing, though neither country will confirm exactly where he is.
Chen's famous for exposing a government program that forced women to have abortions to conform to China's one-child policy. Inside China, he's a man on the run, though the Obama administration has long pushed for his freedom.
Now, top U.S. officials are staying silent on Chen's case. When asked about Chen's whereabouts, President Obama wouldn't even mention his name.
"Obviously," said Mr. Obama, "I'm aware of the press reports on the situation in China, but I'm not going to make a statement on the issue."
Clinton also declined to comment on Chen before flying to China for a pre-arranged series of high-level meetings between Beijing and Washington.
"A constructive relationship," she said, "includes talking very frankly about those areas where we do not agree, including human rights. That is the spirit that is guiding me as I take off for Beijing."
Why isn't anyone talking publicly? It's likely China will only allow Chen to claim asylum in the U.S. if the case is handled quietly.
But Chen might be the one complicating things: His friends say he wants to stay in China with his family -- but out of house arrest.
He might not have a choice.
Chinese officials could decide to expel this outspoken activist quickly.
So far, there's been almost a total media and Internet blackout on the case inside China, but that might not last for long.
To see Celia Hatton's report, click on the video in the player above.