An engineer in Berkeley, California, has been charged with attempting to fatally poison his colleague over a period of several years, Berkeleyside reports. Prosecutors allege that David Xu, 34, a senior materials engineer at Berkeley Engineering and Research, Inc., tried to poison a female co-worker to death by putting cadmium, a toxic metal, in her food and water, court records show. At times, the woman noticed “a strange taste or smell from her water and food” after she had left it unattended in her office. After eating the food, the woman experienced “immediate and significant health problems” that caused her to seek medical attention. Xu was charged with three felonies, including premeditated attempted murder resulting in great bodily injury. Last year, two of the victim's relatives who drank from her water bottle also got sick, police say. Police reportedly obtained surveillance footage that shows Xu pouring a substance into the woman's water bottle on Feb. 11 and March 4. Water samples taken from the bottles on both of those dates tested positive for a toxic amount of cadmium. Blood samples obtained from the victim and her two family members also showed elevated levels of cadmium. Xu is being held without bail in Berkeley City Jail.