Berkeley engineer poisoned co-worker’s water and food for months, prosecutors say

David Xu, an engineer at Berkeley Engineering and Research, was charged with premeditated attempted murder.
(Berkeley Police Department)

A Berkeley engineer has been charged with attempted murder in the alleged poisoning of one of his colleagues over several months, according to prosecutors.

David Xu, 34, of Lafayette, Calif., was arrested last week and charged with premeditated attempted murder and a special circumstance of causing great bodily injury as well as two counts of poisoning with an enhancement, said Teresa Drenick, a spokeswoman with the Alameda County district attorney’s office.

His arrest came on March 28 after police served a search warrant at his home. He is being held in Santa Rita Jail without bail, according to inmate records.

Berkeley police began investigating Xu after his colleague, identified in a criminal complaint as Rong Yuan, reported her suspicion that Xu was poisoning her while the two worked together at Berkeley Engineering and Research, police said.


Yuan noticed a strange taste or smell coming from her water and food that she had left unattended in her office. She told investigators she suffered from health problems immediately after consuming the water and food, requiring her to seek emergency care at a hospital several times, according to court records.

After suspecting Xu, Yuan reviewed surveillance video from her office and saw Xu adding something to her water bottle on two occasions on Feb. 11 and March 4, according to court records. Xu’s criminal complaint also alleges that he poisoned Yuan on Nov. 29 and Dec. 13.

Two of Yuan’s family members reported they also became sick after drinking from Yuan’s water bottle when she returned home from work, according to court documents. Water samples from Yuan’s water bottle on those two dates tested positive for a toxic amount of cadmium. Blood samples from Yuan and her relatives also indicated high levels of cadmium.

According to the Occupational Safety and Health Administration, cadmium is a malleable metal found in zinc and used in batteries. In the short-term, exposure to the metal can cause flu-like symptoms and damage to the lungs. Long-term exposure can lead to several diseases, including cancer.


An employee at Berkeley Engineering and Research declined to speak to a Times reporter Thursday morning.

“I’m sorry, we can’t have any comments right now,” the employee said.

Xu, a UC Berkeley alumnus, is not listed on the company’s staff website.

Twitter: @r_valejandra

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