A researcher at the University of Wisconsin-Madison faces criminal charges after admitting to lacing a coworker’s water bottle and shoes with a dangerous chemical.
A researcher at the University of Wisconsin-Madison’s Influenza Research Institute has been charged with second-degree reckless endangering safety after admitting he laced a coworker’s water bottle and shoes with poisonous laboratory chemicals, according to a criminal complaint and university police reports.
Makoto Kuroda, 41, of Madison, also faces a charge of tampering with household products. He was arrested on April 10 after confessing to Madison police and UW-Madison police officers. He remains held in Dane County Jail on a $5,000 cash bond and is prohibited from entering campus laboratories.
The incident occurred at the Influenza Research Institute, where Kuroda and the victim had worked together since 2017. Kuroda told investigators he was upset about the victim’s second promotion and cited concerns about the victim’s failure to follow lab safety protocols.
Court records obtained by several outlets, including The Daily Cardinal and FOX47 Madison, describe the incident. On April 2, the victim drank from a new water bottle and left it on his desk. Upon returning on April 4, he noticed a strong chemical odor, described as similar to chloroform, and a chemical taste. He immediately spat out the remaining liquid.
Testing by the State Laboratory of Hygiene confirmed a high concentration of chloroform in the bottle residue. Kuroda admitted to using Trizol, a reagent containing chloroform, as part of the mixture.
Kuroda told police he added roughly 0.5 milliliters of 4% paraformaldehyde to the water bottle and, in each of the victim’s shoes, a mixture of 1.5 milliliters of Trizol and 1.5 milliliters of 4% paraformaldehyde — all taken from his own lab fridge. He said he hoped the victim would vomit and suffer skin irritation. He acknowledged that ingesting about 10 milliliters of paraformaldehyde could be critical or lethal.
The victim reported the suspicious odor to UW-Madison police on April 6. Officers, with assistance from the Madison Fire Department Hazardous Incident Team, collected evidence on April 7. Kuroda confessed during questioning and had already informed colleagues of his actions by text and email.
UW-Madison Police Department officials described the case as isolated, with “no known threat to public safety.” The investigation is ongoing, and additional charges may be filed. Kuroda is scheduled for a preliminary hearing on April 21 in Dane County Circuit Court.
