Berkeley Engineer Caught on Video Poisoning Colleague with Cadmium

A California chemical engineer, David Xu, has been captured on video systematically poisoning a colleague with cadmium, a toxic heavy metal, over an 18-month period. Xu, a metallurgist at Berkeley Engineering and Research, targeted Rong Yuan's food and water between 2017 and 2019.

Yuan described the experience as "almost dying" multiple times, stating, "I experienced death so, so close so many times." She expressed a desire for accountability, adding, "I cannot let him go."

During the period of the poisoning, Yuan experienced severe health issues, including debilitating symptoms and frequent hospital visits, while Xu maintained a deceptive demeanor. He suggested her illness was caused by "mold" in the office, even emailing colleagues on November 27, 2018, advising Yuan to "work from home until you feel better" and noting, "I think BEAR is moldy."

The scheme unraveled in early 2019 when Yuan installed a hidden camera at her desk. The footage captured Xu tampering with her water bottle, leading to his arrest in March 2019. He faced charges of attempted murder and poisoning, which also affected Yuan's parents who inadvertently consumed the tainted water.

Following his arrest, Xu was released on $2 million bail. His travel restrictions were later lifted as his home confinement terms were modified. In late 2023, the attempted murder charges were dropped as part of a plea bargain. Xu pleaded no contest to a single felony count of poisoning and received two years of probation, serving only one day of credited jail time.

Yuan had sought nearly $500,000 in restitution, but Xu was ordered to pay only $7,058. He completed his probation in March and is now seeking to have the felony conviction formally dismissed under California's expungement statute, which mandates dismissal for defendants who fulfill all probation terms.