US Engineer Caught on Camera Poisoning Colleague’s Water Bottle

By Micheal Chukwuebuka

A California engineer convicted of poisoning a colleague is seeking dismissal of his felony conviction after completing probation, as the woman releases surveillance footage she says exposed the attacks. David Xu, 41, a metallurgist at Berkeley Engineering and Research, pleaded no contest to one felony poisoning count in September 2023 after prosecutors dropped a charge of premeditated attempted murder.

His former colleague, Rong Yuan, 50, told the San Francisco Standard that she released the recordings because she continued to suffer serious health problems and believed the legal process had failed her. “This legal system already failed me,” she said. “This is my last resort.” Yuan said she experienced repeated bouts of vomiting, hair loss and other unexplained symptoms between 2017 and 2019, leading to hospital admissions and consultations with specialists.

The problems began shortly after she joined the forensic engineering company in January 2017. Both she and Xu had earned doctorates at the University of California, Berkeley, and specialised in metals. Yuan recalled an early disagreement in which Xu told her she could not use the company’s materials characterisation laboratory. “I know how to use all these tools,” she recalled telling him. “I’ve even repaired them.”

She said she subsequently tried to avoid confrontation and concentrate on her work. By July 2017, her symptoms had worsened. After drinking from her water bottle one morning, she became severely ill and a neighbour took her to an emergency department. “I began to feel like I was dying,” she said.

Further episodes prompted additional hospital visits and a trip to China for medical treatment, but examinations did not explain her condition. Her parents later travelled from China to help care for her. When Yuan emailed colleagues on November 27, 2018, describing another episode of vomiting, Xu suggested that conditions in the office might be responsible. “You should work from home until you feel better. No reason to rush in,” he wrote. “I think BEAR is moldy.”