Will a decades-old poisoning case be the next US-China flashpoint?

HONG KONG — Demands for justice in China have just landed on the White House's doorstep.

Over the last several days, Chinese social media have exploded with debate about the unsolved case of Zhu Ling, a pretty, gifted student who was poisoned at Tsinghua University in 1995. Zhu survived, but has been left paralyzed, brain-damaged, and mostly blind.

The primary suspect in the case, Zhu's roommate Sun Wei, was let go after a brief, inconclusive investigation by police. A relative of high-level Communist Party officials, Sun Wei is now believed to be living in the United States under an assumed name.

On Sina Weibo, one of China's most active social media sites, tens of thousands of people urged authorities to re-open the case and bring the culprit to justice. The response: censorship of all searches for Zhu Ling's name, as well as "Sun Wei," and "thallium" — the poison that was put into Zhu's water.

So on May 3, activists created a petition on the White House website asking the Obama administration to "invest [sic] and deport" Sun Wei.

By Monday afternoon, the petition had received over 100,000 signatures, which means the White House will have to issue a response.

Around the same time, censorship of Zhu Ling's name was lifted on Sina Weibo, suggesting a shift in Chinese officials' response.

The controversy around the case was reignited following another student-poisoning incident in April in which Huang Yang, a doctoral student, was killed when a roommate put poison into his water.