A woman whose coworker was convicted of poisoning her is making public the hidden-camera footage that helped expose him, as he seeks to have his felony conviction erased.
Prosecutors said David Xu, a former senior materials engineer at Berkeley Engineering and Research in California, contaminated colleague Rong Yuan’s food and drinking water with cadmium, a toxic heavy metal, over more than a year between 2017 and 2019.
Xu initially faced charges of premeditated attempted murder and two felony poisoning counts. Instead, he accepted a plea agreement involving one poisoning count and one year of probation, entering a no-contest plea, according to the San Francisco Standard. At his 2024 sentencing, the judge extended probation to two years and described the agreement as “extremely generous, considering everything in this case.”
Yuan released footage that appears to show Xu pouring a substance into her water bottle shortly before he was scheduled to ask an Alameda County judge on Monday to dismiss the felony conviction.
David Xu, a former senior materials engineer at Berkeley Engineering and Research, was convicted of poisoning a coworker. He is seeking to have the felony conviction dismissed by an Alameda County judge. (Berkeley Police)
The district attorney’s office has opposed Xu’s dismissal request. However, California law requires judges to grant such petitions when defendants have satisfied the terms of their probation.
Yuan told the Standard that publishing the hidden-camera footage was her “last resort” after what she views as a failure by the legal system to protect her.
Yuan joined Berkeley Engineering and Research in January 2017. She recalled that her first interaction with Xu was uncomfortable, saying he told her she was not allowed to use the company’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.”
Hidden-camera footage released by Rong Yuan appears to show former coworker David Xu pouring a substance into her water bottle at their California workplace. (Credit: Rong Yuan)
Within weeks, Yuan said, she began experiencing symptoms including dry heaving and hair loss. The problems intensified in July 2017 when she took several sips from her water bottle after waking up. “I began to feel like I was dying,” she recalled.
After repeated hospital visits, Yuan emailed her workplace on Nov. 27, 2018, saying she was vomiting and would not be coming into the office.
The Berkeley, California, building that housed Berkeley Engineering and Research, where David Xu and Rong Yuan worked. (Google Maps)
“You should work from home until you feel better. No reason to rush in,” Xu replied. “I think BEAR is moldy.”
Yuan described a similar episode after drinking from the bottle at her desk in January 2019, saying she thought, “I’m going to die.” Her mother later took a drink and noticed a sour taste, prompting Yuan to suspect that someone was tampering with her water. She then bought a spy camera from Amazon.
Yuan installed the camera on her desk on Feb. 11, 2019. At 11:04 a.m., the footage showed Xu reaching toward the area where her water bottle was sitting.
Footage recorded on March 4, 2019, appeared to show Xu pouring an unknown substance into Yuan’s bottle.
“My blood was frozen,” Yuan said after viewing the recording. “I almost died. I experienced death so, so close so many times. I cannot let him go.”
Berkeley is shown with San Francisco visible in the background. (Neal Wong/Getty Images)
Yuan provided the footage to the Berkeley Police Department soon afterward.
Xu finished his probation in March. While he is asking for the conviction to be expunged, it would still remain on his record.
News Media reached out to Xu’s attorney for comment.