Hidden Camera Exposes Chemist Who Poisoned Coworker for 18 Months

(David Xu tampering with colleague Rong Yuan’s water bottle in a cadmium poisoning case. Photo Credit: New York Post)

A California chemical engineer named David Xu has pleaded no contest to poisoning a colleague.

Hidden camera footage shows him allegedly putting something into her water bottle.

Lab tests found cadmium, a toxic heavy metal, in the bottle at levels up to 3.5 million times the federal limit for drinking water.

Xu worked as a metallurgist at Berkeley Engineering and Research.

From 2017 to 2019 he allegedly poisoned his colleague Rong Yuan through her food and drinks for nearly 18 months.

Yuan started getting very sick in 2017.

She often threw up badly and sometimes needed emergency care.

In 2018 she emailed coworkers that she felt unwell and needed a sick day.

Xu replied that she should work from home and there was no rush to come back.

He also wrote that the workplace was moldy.

In early 2019 Yuan set up a hidden camera at her desk.

The footage allegedly caught Xu tampering with her bottle.

He was arrested that March on charges of attempted murder and poisoning.

In 2023 he took a plea deal.

He pleaded no contest to one felony poisoning count, and the attempted murder charges were dropped.

In 2024 he was given two years of probation and ordered to pay 7058 dollars.

Yuan had asked for nearly 500000 dollars for the harm done to her and her family.

Yuan's parents were also exposed after drinking from the bottle.

Her mother noticed a sour taste once.

Xu finished probation in March 2026.

He now wants his conviction wiped out under California's expungement process.

Yuan says she still deals with health problems and cannot work full time.

After seeing the footage for the first time, she said her blood froze.

She also wrote a research paper on the long term health effects on her and her parents and dedicated it to her late father.

🇺🇸 A metallurgist working in Berkeley started experiencing unexplained health issues and set up a hidden camera, which captured her colleague David Xu adding cadmium to her food. https://t.co/X2YhR3Wv1q

— London Baithead (@londonbaithead) October 13, 2026