BERKELEY (CBS SF) — A Berkeley engineer pleaded not guilty Thursday to charges he poisoned a female co-worker and her relatives by lacing her food and water with deadly cadmium and was ordered to be held on $2 million bail.

Wearing a jailhouse jumpsuit, 34-year-old David Xu appeared before Alameda County Superior Court Judge Delia Trevino, pleading not guilty to one count of premeditated murder for allegedly trying to kill his colleague and two counts of felony poisoning for allegedly harming her relatives.

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When it came to bail, Trevino rejected a defense motion for a bail $200,000 and the prosecution’s demand that it be $5 million. She settled on a bail of $2 million, declaring that she couldn’t rule out that Xu was a danger to others despite several letters of support filed by his attorney Julia Jayne.

“Not everybody can get so many letters of support in such a short time,” Jayne told reporters outside the courtroom. “That speaks to his character.”

When asked about the bail, Jayne said: “I don’t think he is a threat to the public.”

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.

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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 the water and food, at times requiring emergency care at a hospital.

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.

Investigators also took blood samples from the woman and her relatives and found that all three had elevated levels of cadmium, Berkeley police Sgt. Jennifer Wilson wrote in a probable cause statement.

Police haven’t said what might have motivated Xu — who was arrested on March 28th — to allegedly poison his colleague at Berkeley Engineering and Research, Inc.

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