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A Stanford Medical School Student Was Arrested for Poisoning Her Classmates' Water Bottles

The suspect had recently sought psychological care and has claimed to be suffering from insomnia, dizziness, depression, and "a disconnection from reality" at the time of the poisonings.

One day in October 2014, a graduate student researcher at Stanford University's Nusse Lab took a drink from her water bottle. According to testimony she later gave to police, the student "immediately experienced a burning sensation in her mouth and throat. Her eyes became irritated and watery. She began salivating uncontrollably. Her throat was burning so bad that she could not even swallow the water."


When she smelled her water bottle, it reeked of paraformaldehyde.

This wasn't the first time a member of the lab had accidentally ingested the toxic chemical. For weeks, researchers in the lab had been sniffing their water bottles before drinking, and multiple times each week, the bottles smelled strongly of paraformaldehyde. But none of the students suspected that they were being intentionally poisoned by the "awkward and quiet" second-year Stanford Medical School student in the lab, Zheng,* who is now being charged with four felony counts of poisoning. ( The Fountain Hopper, an anonymous publication that made waves earlier this year by alerting students to their rights to request their admissions files under FERPA, discovered the case after receiving a tip from a member of the lab on March 19.)

In her account to police, Zheng described her actions as a cry for help: "I am truly sorry for what had happened, but I really didn't mean to harm people. And I… it was me crying out for help and I didn't know."

Zheng had seemed insecure and very stressed, but her behavior didn't come across as abnormal to her peers, just par for the course at one of the most competitive medical schools in the world. The 26-year-old scientist had come to Stanford's Cancer Biology program from the prestigious Agency for Science, Technology, and Research (A-STAR) program in Singapore. As one of her colleagues would testify later, Zheng described Stanford as "a paradise."


It's not hard to see why. Stanford pays meticulous attention to appearances: The sides of campus streets are regularly scrubbed with soapy water, the grass stays absurdly green throughout drought season, and when students struggle, as Zheng apparently did, they tend to do so quietly. The term "Stanford Duck Syndrome" is widely used on campus to describe the way students appear happy and calm above water, while desperately kicking beneath the surface just to stay afloat. Conversations about young people's mental health have become more urgent on campuses across the country in recent years, Stanford's among them. In January, a Stanford senior committed suicide; another overdosed on graduation day last spring, immediately after the keynote speech by Bill and Melinda Gates.

On a campus where graduate students are often referred to as "sketchy grad students," it's unlikely that Zheng stuck out. No one reported her behavior as having been erratic, odd, or out of character. But while no victims or peers reported any animosity towards or from Zheng, victims said that they did not—and "never had any desire to"—spend time with her outside of the lab. She was described to investigators by her victims and peers as "very shy and quiet," "very reserved," "unsure of herself," "awkward," and "strange." According to one victim, Zheng once mentioned that she "had never had a boyfriend, and envied those who had." And while she was seen by older researchers as being "not very confident" in her lab work, Zheng's stressed-out, quiet vibe was pretty much standard at a medical school with an acceptance rate of 2.4 percent, the third-lowest in the country.


Zheng, who had sought psychological care from the university before the poisoning incident, told the Stanford Department of Public Safety that she had been suffering from severe insomnia, dizziness, depression, and "a disconnection from reality" at the time of the poisonings.

She added that she was not conscious of specifically choosing which water bottles to taint. But despite the presence of men and caucasian women in the lab, all of her victims were Asian women—and when one victim threw her water bottle out, Zheng noted that it was missing and asked her why.

Another researcher's mouse stem cell samples had "started to mysteriously die" with "no obvious cause." After successfully cultivating them, the researcher would return to find her cells dead the next morning. "The manner in which they died was very strange," she later told Stanford Public Safety Officer Mike Kim. "The cells detached and floated up dead." After several weeks, the researcher began to suspect she was being targeted. She intentionally mislabeled half of her samples; those labeled correctly with her name died, while the others were spared. The researcher then alerted her supervisor, director of faculty relations Ellen Waxman at Stanford Medical School, who chose to deal with the matter internally. (As of publication, Waxman had not replied to VICE's request for comment.)

When another student came forward with accounts of severe burning in her throat, the University decided it was time to get campus police involved.


Photo via Flickr user Peter Thoeny

On November 11, Zheng was "5150'd"—placed in an involuntary psychiatric hold, in her case by Stanford's Vaden Health Center. She was then held overnight at Fremont Hospital. Around 6:30 in the morning, Zheng called one of Stanford's graduate resident deans, asking why she was being 5150'd when she had readily agreed to be treated. A couple hours later, she called the same dean again, "begging" to be allowed to stay in school, according to court documents. During that same phone call, she confessed to having put substances in her labmates' water bottles, though she did not specify which one. The dean testified that "she stated that she had done bad things but 'not consciously.'"

Zheng allegedly told the dean "I was not myself" and "I didn't mean to hurt anyone." When asked if she was referring to the water bottles and tainted lab samples, Zheng replied, "Yes, but I did not know what I was doing and I did not want to hurt anyone."

Even so, on November 15, Zheng was arrested and charged with the four felonies. The Stanford student body was not informed—according to the University, no campus alert was sent because the suspect was not on campus and posed no threat to the community.

Zheng confessed almost immediately after police begin questioning her, describing her actions as "something like sleep walking." As the police report reads, "At the time, she was psychologically unstable, depressed, stressed and very dizzy. Sometimes the dizziness caused her not to be fully conscious of what she was doing." According to the Fountain Hopper, Zheng's attorney has said that she is currently out on $50,000 bail, awaiting psychiatric evaluation and a May court date.


During her confession, Zheng told investigators that she "should have gone to the doctor and got treated" but instead "she just kept it within her."

Stanford's primary mental health facility is CAPS (Counseling and Psychological Services); students are offered an unspecified number of visits with CAPS psychologists before being referred to outside doctors. Zheng stated in her testimony that she saw a psychologist three or four times before being referred to a psychiatrist, who prescribed her antidepressants.

The antidepressants apparently caused Zheng to have horrible headaches, and she eventually stopped taking the pills. During her confession, Zheng told investigators that she "should have gone to the doctor and got treated" but instead "she just kept it within her."

The school's mental health culture has recently become a hot-button topic on campus, after student journalists at the Stanford Review reported that in the wake of January's student suicide, those who sought counseling from CAPS faced a two-day wait period before a preliminary "screening call" could be conducted. (Stanford declined to comment on all questions regarding mental health services at the university.)

The Lorry Lokey Stem Cell Research Building, which houses the Nusse Lab. Photo via Flickr user Min Liu

Zheng's attorney has indicated in court documents that she may plead not guilty by reason of insanity, which can be a tricky defense to mount—in order for it to work, a lawyer must convince the jury that, due to a mental defect or disorder, their client "was incapable of knowing or understanding the nature and quality of his or her act and of distinguishing right from wrong at the time of the commission of the offense."


"The overwhelming majority [of insanity defenses] fail, because prosecutors and juries want to hold people responsible to their conduct," says Charles Sevilla, the defense attorney in People vs. Skinner, a 1985 case that helped restore a narrow version of California's "right/wrong" insanity test after it had been broadened by a Supreme Court ruling. "Insane people create great fears in the public. The idea of finding a person who has committed terrible, violent acts 'not guilty by reason of insanity' is a disturbing prospect to many people."

Despite seeking treatment for her psychological issues in the past and describing herself as "disassociating" during the poisoning incidents, it's hard to see the insanity defense sticking for Zheng. When asked if she thought that putting chemicals in someone else's water bottle was OK, Zheng told investigators, "I know that it's wrong."

Clarification (4/2/15): Zheng was a PhD student in Cancer Biology at the Stanford School of Medicine. She was not an MD student.

*We have chosen to use a pseudonym for the suspect out of respect for the privacy of all involved. The victims of this case requested that their names not be released, citing concerns for their families and their careers.

Reporting was contributed by the Fountain Hopper.

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