By Christin Ayers

BERKELEY (KPIX 5) — A Berkeley engineer is behind bars Monday night, facing charges that he tried to murder his co-worker by repeatedly poisoning her over the course of nearly a year and a half.

David Xu is accused of premeditated attempted murder in the case. He was working at Berkeley Engineering and Research, Inc.

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According to court records, in October of 2017, Xu began trying to poison a female fellow engineer, Rong Yuan, by mixing “a poison and harmful substance with food, drink, medicine, and pharmaceutical product” that belonged to Yuan.

Yuan allegedly “noted a strange taste or smell from her water and food left unattended in her office,” according to the criminal complaint. She later began experiencing “immediate and significant health problems after consuming this water and food, at times requiring emergency care at a hospital.

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Authorities said in the complaint that Yuan suspected Xu of poisoning her after seeing him appear to slip something in her water bottle on office surveillance video on two separate occasions.  A sample of the water later tested positive for toxic levels of cadmium, a substance that can cause cancer or death.

A blood sample from Yuan also contained elevated levels of cadmium. Xu is also facing charges for allegedly poisoning two of Rong’s relatives who drank from her water bottle.

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An employee reached by phone at Berkeley Engineering and Research, Inc. had no comment on the allegations.