A chemical engineer, who pleaded no contest to poisoning a colleague, was caught on hidden video poisoning a colleague by pouring cadmium into her water bottle.
David Xu, a metallurgist at Berkeley Engineering and Research, spiked his colleague Rong Yuan’s food and water with cadmium, a toxic heavy metal, for nearly 18 months between 2017 and 2019.
“My blood was frozen,” Yuan told The San Francisco Standard of the first time she watched the video. “I almost died. I experienced death so, so close so many times. I cannot let him go.”
Yuan suffered a series of alarming health problems, including persistent vomiting, hair loss, and a strange sour taste in her mouth. Her condition deteriorated to the point that she required repeated hospital visits while struggling to understand what was making her sick.
When Yuan emailed her colleagues on Nov. 27, 2018, to report severe vomiting and take a sick day, Xu responded with chilling nonchalance, The Standard reports.
“You should work from home until you feel better. No reason to rush in,” he wrote, adding, “I think BEAR is moldy.”
The truth emerged after Yuan, suspicious that someone might be tampering with her food and drinks, installed a hidden camera at her workplace.
The footage captured Xu approaching her desk and appearing to pour a substance into her water bottle on separate occasions. Yuan subsequently handed the evidence to police, triggering an investigation that led to Xu’s arrest in March 2019.
After his arrest, Xu was released on $2 million bail. He then received repeated modifications to his home confinement, with his travel restrictions eventually fully lifted, reports The Standard.
In late 2023, under a plea bargain offered by Pamela Price, the former Alameda County District Attorney, the attempted murder charges were dropped.
Xu pleaded no contest to a single felony count of poisoning and received two years of probation, serving just a single day of credited jail time.
Yuan had sought nearly $500,000 in restitution but Xu was ordered to pay only a $7,058 restitution order.
He completed his probation earlier this year in March and is now asking the court to formally dismiss the felony conviction under California’s expungement statute.
Berkeley engineer caught on video poisoning coworker https://t.co/CssRPpKjLl
— PR Media NG (@PRMedia2427) October 12, 2026
