Engineer secretly poisoned colleague with cadmium over two years
A Berkeley engineer poisoned his female colleague with cadmium, a highly toxic heavy metal, between 2017 and 2019, leaving her severely ill with mysterious symptoms whilst he feigned concern. Hidden camera footage eventually caught him contaminating her water bottle, but despite facing attempted murder charges, he received only two years' probation and one day in jail—a sentence the victim views as a catastrophic failure of justice.
David Xu, 41, worked at Berkeley Engineering and Research with Rong Yuan, both with PhDs from UC Berkeley. Yuan began suffering hair loss, vomiting and other severe symptoms shortly after joining the company in January 2017, enduring repeated hospitalizations whilst Xu cryptically suggested mold in the office might be responsible. After installing a hidden camera, Yuan captured footage showing Xu pouring cadmium into her water bottle in February and March 2019. Now, seven years after his arrest, Xu is seeking to have his felony conviction dismissed after completing his probation, prompting Yuan, now 50, to fight the dismissal.
- Engineer poisoned colleague with toxic cadmium, contaminating her food and water for years.
- Caught on hidden camera footage but received only probation despite attempted murder charges.
- Now seeks to dismiss conviction while victim fights to keep it on record.
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Rong Yuan, an engineer at Berkeley Engineering and Research, fell mysteriously ill shortly after joining the company in January 2017. Over the next two years she suffered severe symptoms including hair loss and vomiting, requiring repeated hospitalisations whilst the cause remained unknown.
Her colleague David Xu, also a PhD-trained engineer, was secretly poisoning her with cadmium, a highly toxic heavy metal. Hidden camera footage in February and March 2019 captured Xu contaminating Yuan's water bottle, finally revealing the source of her illness.
Xu was charged with attempted murder and received a sentence of two years' probation and one day in jail. After completing his probation, he is now seeking to have his conviction dismissed, a move that Yuan is contesting.
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The strongest fair case each way — we don't pick a winner.
The case for
The criminal justice system contemplates conviction dismissal after successful completion of probation as a mechanism for rehabilitation and reintegration. Xu has fulfilled the sentence imposed by the court without incident, and the legal principle of allowing dismissal after compliance is designed to give individuals the opportunity for a genuine fresh start. Recognising that people can change and deserve paths to rebuild their lives encourages rehabilitation and reflects the restorative purpose of the justice system alongside punishment.
The case against
The premeditated nature of Xu's crime—deliberately poisoning a colleague over two years, causing severe and lasting harm—warrants permanent legal consequences. The original sentence was already inadequate, and dismissing the conviction would compound that failure of justice. The victim's need for validation of her suffering and the principle that certain crimes merit lasting accountability should outweigh the defendant's interest in erasure, particularly where his actions demonstrated calculated cruelty over an extended period.
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Originally published by Daily Mail as “Berkeley engineer is caught on camera poisoning female colleague’s drink before blaming her illnesses on mold in the office”.