Berkeley engineer charged with trying to poison a colleague to death

David Xu has been charged with trying to kill a colleague by poisoning her with cadmium. Photo: BPD
David Xu has been charged with trying to kill a colleague by poisoning her with cadmium. Photo: Berkeley Police

An engineer in Berkeley has been charged with trying to kill a colleague by putting a toxic metal called cadmium into her food and water since 2017, according to court papers.

Berkeley police arrested David Xu, 34, of Lafayette on a warrant Thursday at 5 p.m., according to jail records online.

For months, according to court papers, a fellow engineer at Berkeley Engineering and Research, at 808 Gilman St., had noticed “a strange taste or smell from her water and food” that she had left unattended in her office. She experienced “immediate and significant health problems” after consuming the food and water, and sometimes sought emergency care at the hospital, police wrote. Two of her relatives who drank from her water bottle in November and December also got sick, according to police.

Surveillance footage from the woman’s office showed Xu adding a substance to the woman’s water bottle on two occasions, Feb. 11 and March 4, police wrote. Water samples taken from the bottle on those dates “tested positive for a toxic amount of cadmium,” according to police.


Authorities also took blood samples from the woman and her relatives and found that all three “had elevated levels of cadmium,” police wrote, adding, “Exposure to cadmium can lead to organ system toxicity, cancer and/or death.”

Police have not said what might have motivated the poisoning.

The Alameda County district attorney’s office charged Xu on Thursday with premeditated attempted murder spanning from Oct. 9, 2017, through March 4, resulting in great bodily injury, according to court records.

Xu also has been charged with two other counts of felony poisoning — on Nov. 29 and Dec. 13 — “which may have caused death and which did cause the infliction of great bodily injury.”

As of Monday, Xu remained in custody at Berkeley Jail and was being held without bail, according to records online. His arraignment is set for Tuesday morning at Wiley Manuel Courthouse in Oakland.

Xu has been scrubbed from the current version of the Berkeley Engineering and Research (BEAR) website. But, according to his resume, which Berkeleyside found through historical searches online, he was the principal engineer at the firm and has been trained in chemical, materials and mechanical engineering. He began his career at BEAR in 2009.

Xu received his bachelor’s, master’s and doctoral degrees at UC Berkeley.


In 2013, BEAR published a notice in the San Francisco Business Times to announce that Xu had passed the state’s engineering examination. The blurb identified Xu as BEAR’s head metallurgist, which is a scientist who works with metals.

Xu was quoted widely in 2013 in connection with the failure of many of the seismic safety bolts used to build the San Francisco-Oakland Bay Bridge. A number of media sources asked him to discuss the metallic properties of the bolts and weigh in on safety concerns.

According to an earlier version of his resume, Xu also did testing in connection with the San Bruno pipeline explosion in 2010.

According to its website, engineers at BEAR “have consulted on hundreds of critical, high-profile projects including the Alaskan Pipeline, the Golden Gate Bridge, the Hercules blowout in the Gulf of Mexico, the Milwaukee Brewers Stadium opening/closing roof design, the Tower Air 747 fire at the Miami airport, [and] the San Bruno pipeline explosion, among many others.”

At one point, according to a prior version of his resume, Xu was offering his services as an expert witness for depositions and trials, charging $350 an hour. One of BEAR’s areas of expertise, according to its website, is litigation support.

According to the company website, with “over 10,000 square feet of testing space, 3D printers, [and] a full machine shop, BEAR performs state of the art development, analysis, FEA and multi-physics simulation, and forensic work on a wide range of products and equipment.” The firm has been around for 25 years and has a number of high-profile clients, from Dow Chemical and PG&E to State Farm, Intel, Conoco Phillips and AC Transit.


Xu ran a materials and metallurgy laboratory at BEAR and wrote, in a promotional statement previously posted on the company website, “With our extensive knowledge in physics, engineering (materials, mechanical and electrical), and experience in testifying, we can solve and explain almost any problem or failure.”

Cadmium is a metal found in the earth’s crust that’s primarily used in batteries, according to the Agency for Toxic Substances and Disease Registry. It is also used in pigments as well as coatings and platings.

“Eating food or drinking water with very high cadmium levels severely irritates the stomach, leading to vomiting and diarrhea, and sometimes death,” the agency reported in 2012.

Exposure to lower levels of the metal over a long time can also cause kidney damage and make bones become fragile and break more easily.

Berkeley Engineering and Research did not respond Monday afternoon to requests for comment.