She checked on the film. The boxes were the same but not the contents. Woeser had given her 19 rolls of exposed Fuji 120 film; the boxes now contained 15 rolls of unexposed Kodak 135 film.

That led Woeser to suspect that listening devices had been planted in our home. Her request to her friend had been made orally and to her alone. No one else had been involved; no telephone or Internet communications were used. That was why I was carrying the probe hound. We wanted to know whether our home was bugged.

I told all this to the police and then asked them to return the probe hound. They refused. It was “counterespionage equipment,” I was told. Citizens have no right to own such a device.

These things happened as the Edward Snowden revelations were attracting the world’s attention. The Chinese government seemed gratified, even pleased. Look! The United States is no better than China, so let’s all just stop the mutual carping.

But let’s not jump to conclusions. How comparable are the cases? Is it conceivable that the United States would tell a citizen that he has no right to a probe hound?