David Xu, a former senior materials engineer at Berkeley Engineering and Research in California, poisoned his colleague Rong Yuan with cadmium from 2017 to 2019, according to prosecutors. Xu faced charges including premeditated attempted murder and two felony counts related to the poisoning. He accepted a plea deal for one count of poisoning, receiving one year of probation. At the 2024 sentencing hearing, a judge extended probation to two years, calling the deal "extremely lenient, considering all that happened in the case".

On 12/10, Yuan publicly released a video showing Xu pouring a substance into her water bottle. This release came just before Xu requested an Alameda County judge expunge his felony conviction. The district attorney's office opposed Xu's request. However, California law mandates judges grant such requests if the convicted person meets probation conditions. Yuan called the video's release her "last resort" against a legal system that had frustrated her.

Video released by Rong Yuan shows former colleague David Xu pouring an unknown substance into her water bottle at their California workplace.

Yuan joined the company in 1/2017. She recalled initial tension with Xu, who told her she couldn't use the materials characterization laboratory. Yuan decided to avoid working concurrently with him. Weeks later, Yuan experienced dry heaving and hair loss. Her condition worsened in 7/2017; after drinking from her water bottle, she felt "like she was going to die". In late 2018, after multiple hospital visits, Yuan emailed the company on 27/11 about her vomiting. Xu replied, suggesting she work from home due to suspected mold. In 1/2019, Yuan again fell ill after drinking from her desk bottle. Her mother tasted it, noticing an unusual sourness, leading them to suspect tampering.

Yuan then bought a hidden camera online. On 11/2/2019, she placed it on her desk. Footage captured Xu reaching towards her water bottle at 11h04. Another recording from 4/3/2019, showed Xu pouring something into Yuan's bottle. 'My blood ran cold. I had been very close to death multiple times. I couldn't let him get away with it', Yuan recounted. She promptly delivered the evidence to the Berkeley Police Department.

David Xu received a two-year probation sentence after poisoning his colleague for an extended period. Photo: Berkeley Police

Xu completed his probation in 3/2026 and is petitioning the court to vacate his felony conviction. If approved, this could allow Xu to be considered as not having a conviction in civil proceedings, such as job applications. However, the case file remains accessible to law enforcement, courts, and authorized bodies.

Tue Anh (according to Fox News, San Francisco Standard)