A California man caught on camera poisoning his colleague’s water bottle wants the charges against him dismissed.
Police arrested David Xu in March 2019 after surveillance footage showed he placed toxic metal cadmium in his coworker Rong Yuan’s water bottle at their workplace.
Yuan set up a secret camera on her desk, which captured Xu opening a small white container and pouring its contents into her bottle. She later shared the footage with local media.
Yuan recalled a tense initial encounter with Xu at Berkeley Engineering and Research (BEAR) in 2017, when he told her she couldn’t use the firm’s material characterization lab.
“I just decided I will never overlap with him,” she said. “I’ll just simply do my work, and he can do whatever he wants.”
Yuan told The San Franciso Standard that she began experiencing illness a few weeks later and continued to suffer health problems over the following two years.
The illness caused her to experience hair loss, and she even had to miss work because of vomiting.
Yuan says Xu appeared concerned when she told him that she had been vomiting.
“You should work from home until you feel better. No reason to rush in,” he told her. “I think BEAR is moldy.”
Yuan then noticed that drinking from her water bottle often made her feel sick.
In January 2019, Yuan’s mother drank from the water bottle and noticed a strange sour taste. It was then that Yuan began to suspect someone was tampering with her water.
So, she ordered a spy camera from Amazon.
That camera caught Xu poisoning her water in February and March of 2019.
In one video, Xu flees quickly after pouring the contents. He briefly returns to adjust the position of Yuan’s water bottle.
Yuan then turned the evidence over to the police.
“My blood was frozen,” Yuan told The Standard. “I almost died. I experienced death so, so close, so many times.”
Xu was convicted on one count of poisoning in September 2023. A second count of poisoning and an attempted murder charge were dropped as part of a plea deal, according to court records reviewed by The Berkeley Scanner.
A judge handed Xu two years’ probation, which he completed in March.
Xu appeared in Alameda County Superior Court on Monday, more than seven years after the two recorded poisonings took place. He asked the judge to dismiss his felony conviction.
Under California law, people who complete probation can petition the court to expunge their records, allowing them to withdraw a guilty or no-contest plea and have the case dismissed.
The court agreed to expunge his conviction despite objections from the Alameda County District Attorney’s Office.
The Standard reviewed a lab report that revealed samples taken from Yuan’s water bottle tested positive for an immense level of cadmium — up to 3.5 million times the federal limit for drinking water.
The World Health Organization classifies cadmium, a heavy metal, as a carcinogen that can damage the kidneys, bones, and respiratory system.
Speaking to the publication, Yuan says she’s concerned that a dismissal will result in Xu’s conviction not being visible to future employers.
“This legal system has already failed me,” she said. “This is my last resort.”
Yuan says the poisoning left her with long-term health problems that prevent her from working full-time. She sought nearly $500,000 in restitution, but a judge ordered Xu to pay her just $7,058.
Yuan recently published a research paper documenting the long-term effects of cadmium poisoning on her and her parents.
Through her research, Yuan hopes to help doctors recognize the warning signs of cadmium poisoning sooner and prevent other families from enduring what hers did. “So, this doesn’t happen again,” she said.
