Video Exposes California Engineer's Poisoning of Colleague, Triggering Severe Illness

A California chemical engineer, David Xu, was reportedly captured on a hidden camera systematically poisoning a coworker, a crime to which he later pleaded no contest. Xu, who worked as a metallurgist at Berkeley Engineering and Research, is alleged to have spiked his colleague Rong Yuan's food and beverages with cadmium, a highly toxic heavy metal, for approximately 18 months between 2017 and 2019.

Recounting her initial reaction to viewing the incriminating footage, Yuan expressed profound horror to The San Francisco Standard, stating, “My blood was frozen.” She further conveyed the severity of her ordeal, adding, “I almost died. I experienced death so, so close so many times. I cannot let him go.” Throughout this period, Yuan endured a range of distressing health complications, such as continuous vomiting, significant hair loss, and an inexplicable sour taste. Her health spiraled downwards, necessitating numerous hospital visits as she grappled with the mystery of her deteriorating state.

An email sent by Yuan on November 27, 2018, to her colleagues, reporting severe vomiting and requesting a sick day, received a chillingly casual response from Xu, according to The Standard. Xu advised, “You should work from home until you feel better. No reason to rush in,” and then added, “I think BEAR is moldy,” referencing their workplace.

The truth behind Yuan's illness came to light after she, suspecting foul play with her food and drinks, installed a covert camera in her office space. The recorded video evidence showed Xu approaching her workstation and appearing to introduce a substance into her water bottle on multiple occasions. Yuan subsequently presented this crucial evidence to law enforcement, which initiated an investigation and ultimately led to Xu’s arrest in March 2019.

Following his arrest, Xu was released on a $2 million bail. He subsequently benefited from several adjustments to his home confinement conditions, with all travel restrictions eventually being lifted, as reported by The Standard. In late 2023, a plea agreement facilitated by Pamela Price, then the District Attorney for Alameda County, saw the attempted murder charges against Xu dropped. He instead pleaded no contest to a single felony count of poisoning, resulting in a sentence of two years' probation and a mere single day of credited jail time. While Yuan had sought nearly $500,000 in restitution, Xu was mandated to pay only $7,058.

Having completed his probation in March of this year, Xu is now petitioning the court to formally expunge his felony conviction under California's expungement statute. Under the state’s legal framework, judges are obliged to grant record dismissals to defendants who successfully fulfill all conditions of their probation.