A graduate student at Stanford’s School of Medicine has been charged with four felony counts of “poisoning any food, drink or medicine” for putting paraformaldehyde (PFA) in labmates’ water bottles.

According to a case summary provided to The Daily, the suspect “willingly mingle[d] a harmful substance, paraformaldehyde with a drink, water.”

The suspect has pleaded not guilty by reason of insanity and is no longer a student at Stanford. The University issued a Stay Away Letter to the individual on Nov. 11.

The labmates found PFA in their water bottles in multiple instances during the months of September through November. While two students reported drinking the tainted water and having adverse reactions, a third water bottle was also found to contain a lower amount of PFA.

Prior to these incidents, the graduate student was also suspected of damaging and sabotaging the samples of another researcher in the lab.

According to University spokeswoman Lisa Lapin, Stanford began investigating the situation as soon as a concern was brought forward in mid-November.

“Police referred their findings to the Santa Clara District Attorney,” Lapin wrote in an email to The Daily. “An arrest was made as soon as the suspect was available to be arrested — the length of time between the launch of the investigation and the arrest had to do with the availability of the suspect.”

She also explained that no AlertSU or notification was sent out because the suspect was no longer on campus at the time when the investigation began, and therefore, the suspect was not considered an immediate threat to the University.

“The University acted immediately upon learning of the concerns, and the criminal proceeding under way is a result of the Stanford police investigation,” Lapin said. “This was a confined, isolated circumstance, and there was no threat to the broader campus community.”

Although the suspect admitted to damaging research samples and using a pipette to put PFA in the water bottles, the suspect claimed to be “not conscious” of the act at the time. The suspect had reportedly begun experiencing insomnia and dizziness in September and apologized for allowing those personal issues to progress.

“I am truly sorry for what had happened, but I really didn’t mean to harm people,” the suspect said in a police report contained in the case summary. “It was me crying out for help, and I didn’t know.”

The suspect also claimed to have added chemicals to their own water bottle without having an adverse reaction.

“The victims in this case have asked from the outset of their initial report that the matter remain private,” Lapin stated. “They have reason to request privacy, and the University has respected this request.  In addition, both privacy laws — FERPA and HIPAA — limit what the University can share.”

“This was a sad, heartbreaking situation, and no one could speculate as to why,” she added. ”The University has been providing support to the group impacted. They are a strong team and from the outset requested privacy to move on.”

According to the Santa Clara County District Attorney’s Office, the suspect could face up to nine years in prison and is scheduled for a court appearance on May 15.

Editor’s note: The Daily has not published the name of the suspect in order to protect the identities of the alleged victims, the suspect’s labmates.

An earlier version of the title incorrectly called the suspect a medical student.  The suspect was a graduate student who worked at the School of Medicine but was not a medical student.  The Daily regrets this error.

Contact Kylie Jue at kyliej ‘at’ stanford.edu.