A victim in California, who was poisoned by her jealous former colleague, spoke out for the first time to the media on Saturday, October 10th, after the perpetrator was sentenced to just one day in jail.
The perpetrator, David Xu, a former engineer at Berkeley Engineering and Research, repeatedly put toxic cadmium in the water bottle of his Chinese coworker, Rong Yuan, out of envy. Both Xu and Yuan studied under materials scientist Robert Ritchie at the University of California, Berkeley, where Yuan joined the company later than Xu.
According to the Berkeley Police Department report, over an 18-month period, Xu contaminated Yuan’s food and drinking water with cadmium, leading to her severe illness. Cadmium poisoning can cause organ system toxicity, cancer, or death, the authorities stated.
Tests conducted by the police on the water from Yuan’s bottle, as well as blood samples from Yuan and her parents, revealed extremely high levels of cadmium, up to 3.5 million times the federal drinking water standard. Yuan’s mother even used the water from the contaminated bottle to cook for the entire family.
The poisoning case dragged on for five years, with delays and changes in prosecutors’ offices, fading from public view. It wasn’t until a new district attorney’s office withdrew the most serious charges and in September 2023, both parties reached a plea agreement. Xu admitted to the poisoning charge, and the prosecution accepted a two-year probation and a symbolic one-day jail sentence.
The district attorney lost favor with voters due to his lenient stance on reducing imprisonment rates and was subsequently removed from office.
Xu completed his probation in September 2025. He is scheduled to have his felony conviction record expunged by the Alameda County Court on Monday, October 12. This process is commonly referred to as “expungement.”
Yuan decided to attend the hearing and speak out. Prior to this, she publicly shared a video of Xu poisoning her for the first time and recounted her ordeal.
Wilson, an officer in the Berkeley police homicide division, was assigned to the case. “It was truly shocking,” Wilson said upon viewing the video for the first time. “Without the evidence, no one would have believed her… this case was rapidly investigated due to this video.”
Yuan revealed that during their initial interactions at the company, tensions were palpable as Xu forbid her from using the materials characterization lab. Feeling uncomfortable, Yuan attempted to distance herself from Xu.
In the following two years, Yuan’s health deteriorated, starting with dry retching and hair loss, escalating to frequent vomiting and a persistent sour taste in her mouth. Despite multiple emergency room visits, no diagnosis was made.
To uncover the cause of her illness, she purchased a covert camera from Amazon. On February 11, 2019, she installed the camera by her desk, capturing Xu tampering with her water bottle, providing crucial evidence for the case.
Yuan sought a compensation of nearly $500,000, but the judge ultimately ordered Xu to pay $7,058, citing a toxicologist report submitted by Xu’s lawyer, which claimed that cadmium poisoning wouldn’t have long-term health effects.
Yuan contested the toxicologist’s report, publishing a research paper on the long-term health consequences of cadmium poisoning that she and her parents endured. Her study aimed to aid doctors in early identification of cadmium poisoning symptoms.
Yuan considered filing a civil lawsuit against Xu for damages but abandoned the idea after consulting with a lawyer, who warned of a protracted and costly litigation potentially without any compensation.
The district attorney’s office opposed Xu’s application to expunge his conviction record. However, according to California law, if Xu fulfills all the conditions of his probation, the judge must approve the expungement request.
An expunged conviction doesn’t erase the entire case, and when applying for licenses issued by the California government, Xu must disclose his conviction record truthfully.
Wilson, with over 20 years of experience as a homicide detective, admired Yuan’s resilience in standing up against Xu despite her severe illness. “She never let him win – she kept fighting back even when she was gravely ill, and she keeps at it now,” Wilson expressed.