It sounds like the prosecutors’ cases are disintegrating.

China’s crackdown on free expression on the Internet hit difficulties after two high-profile cyber-dissident cases were forced into the spotlight Monday — one over lack of evidence and the other after witnesses alleged police forced them to testify.

Prosecutors bounced back to police a case implicating one of China’s youngest dissidents — a student known as “Stainless Steel Mouse” detained for posting essays calling for democracy on the Internet.

The case of Liu Di, 22, a psychology student taken into custody from her Beijing Normal University dormitory last November, was returned to police Friday due to insufficient evidence, said sources, including her family.

In the other case, an appeal trial of four Internet dissidents opened Monday to decide if they deserved up to 10 years in jail for posting their views on social issues online, relatives and a Hong Kong-based rights group said.

That case is seriously flawed because three key witnesses retracted their statements used as evidence after they were released from detention, claiming police had forced them to make the claims, said Frank Lu, director of the Hong Kong Information Center for Human Rights and Democracy.

I am thrilled that there might be a happy ending to this nightmare. It’s still too soon to tell, but simply seeing it being covered is a good sign. It’s important to remember, however, that these were two very high-profile cases, followed closely by leading human rights groups. Are there others locked up for similar crimes who weren’t lucky enough to draw international outrage? I can’t say for certain, though I have my suspicions.