MOURNING: A student from Fudan University ties a paper crane on a campus fence in memory of poisoned Huang Yang on April 18 (CFP)

A troubling case of poisoning in April left the student body of Shanghai's prestigious Fudan University paralyzed with grief.

On April 16, Huang Yang, a 28-year-old third-year medical student in the graduate school of Fudan University, died of poisoning by a highly toxic chemical compound named N-Nitrosodimethylamine (NDMA).

Huang became critically ill on April 1. He was hospitalized and his condition quickly deteriorated. He soon suffered liver failure and fell into a coma, but doctors could not find the cause of his illness.

Nine days later, Huang's senior schoolmate received a message from a stranger, telling him to look into NDMA. Doctors later determined that Huang was poisoned with the toxic compound.

Fudan University's security department reported the case to the police on April 11. Police investigations confirmed Huang drank NDMA-contaminated water from a dispenser in his dormitory hours before his hospitalization. Huang's roommate, surnamed Lin, was detained by police on the second day.

Lin, 27, was also a medical student in the same university. He often tested NDMA on guinea pigs to see whether type-B ultrasound can detect liver fibrosis caused by the carcinogen. Lin has published papers based on the experiments.

On April 25, Lin was arrested and charged with murder. Police accused him of putting poison he had acquired for a laboratory test into the water dispenser on the afternoon of March 31.

Trivial motives

Both victim and suspect were top graduate students at Fudan, having won scholarships and published papers in renowned academic journals.

Shortly before his death, Huang took a written examination to enter the doctoral program of Fudan University's Shanghai Medical College, and he ranked first among candidates in his major.

Lin was the winner of the 2012 national scholarship for graduate students. Only 265 grad students at Fudan University have won this honor, according to the China Youth Daily. Latest data from the university show that it has more than 13,000 students enrolled in graduate programs.

However, the two are said to differ remarkably in personality.

Huang was upbeat and outgoing, and popular among girls, said Huang's friend known by his online name "Yuniangniang Doctor."

Huang was also active in volunteering. In the summer of 2010, he taught for one month in a primary school in Medog County in Tibet Autonomous Region and he planned to teach there again this summer.

Lin is said to be serious and not very talkative. One of Lin's classmates in Fudan University told The Beijing News that he was on good terms with others.

Another classmate surnamed Wu said that Lin is a little self-centered and does not care much about others' feelings. A girl once romantically involved with Lin told Shanghai-based Dongfang Daily that his personality is a little odd.

The public speculated that fierce academic competition may have pitted the two against each other. Yet, Fang Ming, a spokesman for Fudan University, dismissed the rumor, saying that the two majored in different fields and interned at different hospitals. Huang studied ear-nose-throat clinical science while Lin specialized in type-B ultrasound.

Shanghai police revealed that Lin had held a grudge against Huang because of trivialities, but did not give any details.

A friend of Huang told Beijing-based Blogweekly magazine that Huang once joked about Lin being stingy.

Lin's classmate, surnamed Chen, told Blogweekly that Lin did not soon forgive offenses, although he might not show it overtly. Chen has known Lin for eight years.

The Fudan poisoning is reminiscent of another poisoning at Tsinghua University in Beijing in 1994. Thallium poisoning left gifted and good-looking chemistry major Zhu Ling paralyzed, severely mentally disabled, and almost blind.

Thallium is an extremely toxic soft grey metal. Thallium itself and compounds containing the element are tasteless, odorless and colorless when dissolved in water. Even skin contact can be fatal.

Zhu's roommate, Sun Wei, who then had legal access to thallium, was questioned by the police as a suspect, but charges were never pressed and the case remains unsolved.

Sun is believed to reside in the United States under another name. On May 3, people sympathetic with Zhu submitted a petition to the White House to investigate and deport Sun. The White House is obligated to respond to petitions receiving 100,000 signatures within 30 days. Signatures on the petition involving Sun reached this threshold after only three days.