The detective work we do in my lab involves genes and cancer cells, not crimes. Or so I thought, until several years ago, when one of my graduate students at the University of Michigan e-mailed me to say that her research had been sabotaged.

"I went to transfect cells today and found there were massive amounts of alcohol in my media," she wrote. "Does someone have a grudge against me?" When I sniffed one of the flasks that were used to feed her cells, I found she was right: It reeked of alcohol, enough to kill the cells. I asked if she suspected anyone. She said no.

We have all read about incidents of scientific misconduct; in recent years, a number of manuscripts based on fake research have been retracted. But they usually involved scientists who cut corners or fabricated data, not deliberate sabotage. The poisoned flasks were a first for me. Falsified data is a crime against scientific truth. This was personal.

I turned to my colleagues to ask how to respond, and to my surprise, they all said the same thing: My student, Heather Ames, was probably sabotaging herself. Their reasoning? She wanted an excuse for why things weren't working in her experiments. Competition and the pressure to get results quickly is ever- present in the world of biomedical research, so it's not out of the question that a young scientist might succumb to the stress.

Heather was working to understand how a protein called HIP1 alters signals within cancer cells in a way that promotes their survival and proliferation. If we could understand how the protein works, we might be able to treat cancer by fixing the corrupted signalling. The idea sounded good, but testing it was not for the faint of heart. I hadn't considered the possibility that Heather was ruining her own experiments, but it made some sense. After all, I knew from Alfred Hitchcock and TV mysteries that the people closest to a victim are usually the main suspects.

The next morning I told Heather allegations of sabotage were serious, and that we could pretend we'd never had the conversation, if that's what she wanted. I was hopeful she'd say yes. Instead, she persisted. So I did the same.

I got in touch with the university's authorities. The experts in charge of oversight were concerned and compassionate, but they also felt that Heather was a possible culprit. There was nothing in her behaviour that suggested anything but a sterling character and devotion to science. But, once again, the suggestion made me fear it was true.

The tampering with Heather's work continued and we ultimately called the police. This was not a simple case of vandalism, I told them, but tampering with cancer research in which substantial resources had been invested. They sent a detective who helped me construct a detailed list of suspects. We started by identifying those who had access to the lab (students, staff), then narrowed it down to people who might have a grudge against Heather. We also looked at people who might hold a grudge against me - anyone I'd offended or let go in the past. But in the end, he too felt Heather was the prime suspect.

So now what? The only thing left to do was install hidden cameras. In April 2010, a few months after Heather's e-mail, the hidden cameras revealed the culprit: a post-doctoral fellow named Vipul Bhrigu, who, confronted with the video, confessed that he had sprayed alcohol into a cell culture medium in the refrigerator. We were in shock. Bhrigu was the most cooperative, passionate and friendly member of my lab. He'd been at the bottom of our suspect list.

After being taken to the police station, he and the detective returned to my office. "I am sorry," he told me. "I have disgraced myself, hurt you, hurt the lab and know that you will never forgive me. I felt terrible every time I did this and almost hoped there was a camera. I thought Heather was so smart and I did it to slow her down. It was because of my internal pressure." Were we dealing with a sociopath, or was he being honest?

Obviously we can't tolerate fraud, but the culture of scientific research may deserve some blame. There is more pressure than ever for researchers to generate huge amounts of data to publish high-impact papers. Those who publish less get less funding. We need a culture change. If we want to protect the integrity of our research, we need to protect the sanity of our researchers. Besides, good science happens when there is freedom to make mistakes, to learn from those mistakes, to discover the unexpected. Unrelenting pressure makes diamonds, not discoveries.

Dr Bhrigu was convicted of a misdemeanour. The judge sentenced him to a psychological evaluation, to probation and to pay US$30,000 (S$42,000) in restitution to the University of Michigan. While on probation, he returned to India. I did, however, hear from the prosecution a few years later that he'd finished his probation after all and paid his fine in full.

Heather - Dr Ames, now - completed her PhD with flying colours. She is a top-notch pathologist and cancer biologist at Johns Hopkins University. She studies brain cancer. Nothing gets in her way.

In the aftermath of our investigation, many people assumed I would be embarrassed that something like this had taken place in my lab. But when I talked about the episode and the lessons we learnt, other researchers came forward with their own tales of sabotage, fraud or plagiarism. Many regretted not solving their cases or prosecuting those responsible, or discussing the events with the wider community.

I was proud we'd got to the bottom of it, and I appreciated the way our crime drama had mirrored the scientific method itself. Only after gathering real evidence did we uncover the truth. One good experiment (videotaping the event) was worth more than all the guesses - all of which turned out to be wrong.

We need to test what we believe, not trust it. This axiom is especially important in a "post-truth world" where we must work even harder to question our assumptions, whether in science, medicine, justice or any other field of problem solving.

NYTIMES

• Theodora Ross, an oncologist and director of the cancer genetics programme at the University of Texas Southwestern Medical Centre, is the author of A Cancer In The Family.