Shocking: Man caught on CCTV after poisoning coworker for 18 months [Video]

A California chemical engineer who pleaded no contest to poisoning a colleague was putting cadmium in her water bottle, new video shows.

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.”

As Yuan suffered debilitating symptoms, hospital visits and fear of a terminal illness, Xu maintained a deceitful facade, even suggesting her illness was caused by “mold” in the office.

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.”

His poisoning campaign only unraveled in early 2019 when Yuan set up a hidden camera at her desk, capturing Xu in the act of tampering with her water bottle.

The video evidence led to Xu’s arrest on charges of attempted murder and poisoning, which also affected Yuan’s parents, who had inadvertently consumed the poisoned water.

David Xu faced up to life in prison for poisoning his colleague, but instead got probation and one day in jail.Courtesy Rong Yuan

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.

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.

Under California law, judges are bound to grant record dismissals to defendants who fulfill every term of their probation.

Engineer caught on video po1soning coworker before she suffered horrific health problems pic.twitter.com/yzm2WTxeIj

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October 12, 2026