Stephen Suomi is one of America’s top animal researchers. Suomi, who is now pushing 70, has dedicated his life to studying childhood development in monkeys. He is among the bigger names in Attachment Theory, the now-mainstream idea that strong parent-offspring relationships are essential to a child’s healthy emotional development. Suomi’s illustrious career spans nearly five decades.

But Congress says he also tortures and kills baby macaques.

Four U.S. congressmen surprised the research community last month by sending a harsh letter to the National Institutes of Health, alleging that in Suomi’s lab, infant monkeys scream for their mothers, their rubbery faces contorted into terrified snarls. The letter cited videos, photographs and reams of documents obtained by People for the Ethical Treatment of Animals (PETA) that appear to show Suomi intentionally traumatizing his monkeys to record their decline into depression and madness.

When I first began looking into the allegations several weeks ago, NIH wouldn’t respond to the charges. Suomi, however, was eager to tell his side of the story. In his first interview since the controversy began, Suomi told me those videos were “all made up” and “the specific allegations in that [congressional] letter are bogus.” He stressed that he has never performed painful, invasive procedures on his monkeys.

But things got murkier last week when the NIH sent its official response to Congress. The agency broadly defended Suomi’s experiments, but agreed to stop performing invasive procedures, like spinal taps, on lab monkeys. What was odd about the response was that Suomi assured me he never performed such procedures on his monkeys in the first place.

So who is telling the truth? Did Suomi torture baby monkeys, or has he been framed?

Meet Stephen Suomi

I first spoke with Suomi over the phone last month. We chatted for an hour about how he got started with the work that he fondly refers to as “monkey business.” Suomi told me that his research career began with a childhood love for animals. Growing up near the city limits of Madison, Wisconsin, the young Suomi loved playing in the nearby forests. “I could watch squirrels and raccoons,” Suomi says. “I was fascinated by that.”

He went on to study psychology at Stanford, and might never have gone into animal research had it not been for a chance meeting between his father and a well-known scientist named Harry Harlow.

Harry Harlow studied baby monkeys as they interacted with cloth-covered fake "mothers." University of Wisconsin-Madison Archives

Harlow was perhaps the most controversial animal researcher of the 20th century, and he definitely did terrible things to monkeys. Harlow developed an isolation chamber that he nicknamed “the pit of despair,” where baby monkeys were locked in darkness for months at a time. He also invented a so-called “rape rack,” so that male monkeys could impregnate females too traumatized to mate. Even at the height of Harlow’s career (he was active from the mid-’40s until the early ’70s), a few of his doctoral students were disillusioned by his grislier experiments.

In 1974, Harlow told the Pittsburgh Press:

The only thing I care about is whether a monkey will turn out a property I can publish. I don’t have any love for them. Never have. I don’t really like animals. I despise cats. I hate dogs. How could you like monkeys?

Nonetheless, Suomi’s father arranged a meeting between Harlow and his son. Suomi remembers telling Harlow about his plan to study psychology in graduate school, as well as Harlow’s lukewarm response. “He sat for a moment and said, ‘Well, Steve, that’s really interesting. But if you do that, you’re going to have a very narrow background. Why don’t you come work for me?'”

Suomi left Stanford and immediately began to work with Harlow at the University of Wisconsin. Three years later, Harlow retired and named Suomi his successor. Although Suomi enjoyed his time in Harlow’s lab, he told me that some of Harlow’s research disturbed him greatly. “I didn’t like his efforts to create depression in monkeys,” Suomi says. “I had to watch the monkeys every day. And you get personal relationships when you see them day after day.”

Suomi told me that he resolved to spend his career studying how to rehabilitate traumatized animals. When he began working for a branch of NIH in 1983, Suomi says, he carried that mission with him into his government-funded laboratory.

“Terrifying and Painful Experiments”

That’s not quite the story that animal rights activists tell. PETA has been lobbying Congress to stop Suomi since at least September, when it obtained damning videos and photographs of wailing monkeys through a Freedom of Information request. I spoke with Justin Goodman, director of laboratory investigations at PETA, who told me this:

Steve Suomi has continued the disturbing legacy of his mentor Harry Harlow by conducting maternal deprivation experiments on what is probably by this time thousands of baby monkeys in his lab at NIH. What these experiments involve is breeding innocent monkeys to be predisposed to depression and other mental illnesses, ripping them from their mothers at birth to traumatize them intentionally, and then subjecting them to years of terrifying and painful experiments.

Not everyone in the research world agrees about what you can and can’t do to monkeys in the lab. Most people believe that researchers should minimize trauma to animals. In fact, there are even federal laws to protect laboratory animals from excessive cruelty. But some scientists generally embrace a more liberal philosophy—arguing that experiments on animals can be justified by how much humanity stands to gain.

PETA takes the most extreme position. It says that all animal research that does not benefit that particular animal is inherently unethical. PETA runs an extensive operation with 300 employees and, according to its website, over 3 million members and supporters worldwide. Its loud protests and graphic images draw plenty of scrutiny, and PETA refuses to condemn the extremist Animal Liberation Front, which has firebombed some animal labs. But for all its bluster, PETA tends to stay within the law. Its investigators seldom, if ever, lie about animal cruelty.

And yet Suomi says PETA is lying about him.

Suomi told me he does not breed monkeys to be predisposed to mental illnesses. (He claims that he doesn’t have to, since about 20 percent of all monkeys are depressed anyway.) Suomi also says he never performs brain surgery or invasive procedures on the monkeys, except when they get their blood drawn during regular veterinary checkups. He told me he collects most of his data from hair samples, and that he certainly does not kill or torture his monkeys.

“Our interest is in their health and well-being,” Suomi says. “If they are not healthy, we don’t know how valuable their data would be. We have a very dedicated staff of animal caretakers and researchers who feel privileged to be able to work with these beautiful animals.”

I asked Suomi why PETA would lie about him, putting his livelihood and reputation at risk. “I’m as big a target as you can imagine,” he says. “I do a lot of public speaking, I’m involved in larger research projects—and if they can bring me down, they can bring anybody down.”

After hearing from Suomi, I was inclined to believe him. Suomi is charismatic and sincere-sounding, over the phone anyway. He suggested that we continue our conversation in his government-funded lab in Maryland and invited me for a visit. Suomi sent me the address, told me what date to show up and informed me that my camera crew and I would have to get a bunch of vaccinations, for the safety of the monkeys.

I got my shots, but less than a week before my scheduled visit, I received a phone call from NIH press officer Robert Bock. He told me Suomi was not feeling well and, regrettably, he wouldn’t be able to meet with me. I called Suomi, who told me, in fact, he was feeling fine. I called Bock, and told him I planned on keeping our appointment.

But Bock called again the next day. This time he told me the lab had received multiple threats from animal rights activists, and he did not feel it was safe to allow my camera crew on the premises. I agreed to show up alone, without the camera crew. Bock said he’d call me back.

Bock did not call me back. When I called him a couple of days later, he told me he was “not getting any support” to bring me into the lab. When I asked him for a specific reason why, he told me that the conversation was over. I have been unable to reach Bock or Suomi since.

But I have heard back from PETA.

Documents That Challenge Suomi’s Story

When I ran Suomi’s denial by Goodman, he literally laughed into the phone.

Goodman reminded me that PETA obtained its damning videos from the NIH itself, through an official request under the Freedom of Information Act. “The NIH has had every opportunity to claim that those experiments were not Suomi’s,” Goodman says. “I am 100 percent confident that these are his monkeys, based on the documentation that the NIH sent us.”

Suomi's signature appears on each of the Animal Study Proposals that PETA sent us. PETA, via FOIA

Goodman sent me a point-by-point rebuttal of everything that Suomi said, along with reams of documents, protocols and studies that bore Suomi’s signature. Regarding Suomi’s claim that he does not breed his monkeys for depression, Goodman points to the following proposals that seem to suggest the lab did just that and more.

Excerpt from an NIH Animal Study Proposal that names Suomi as principal investigator. These protocols were approved in 2011 to run through May 2014. PETA, via FOIA Request

In response to Suomi’s claim that his monkeys were never deliberately killed, Goodman sent me the following paper, which describes those monkeys being killed and dissected at the age of 7.

Excerpt from a 2014 article published in the journal Neuroscience that talks about removing the brains of monkeys raised in Suomi's lab. Suomi is listed as an author of the paper. PETA, via FOIA request

I would have liked to ask Suomi about these protocols, but even after I sent an email to Bock, the NIH spokesman, specifically telling him that I had this information from PETA and wanted to clarify, he refused to let me visit Suomi’s lab. And since my last conversation with Bock, Suomi has stopped returning my phone calls.

Cutting-Edge Research or Junk Science?

Over 1 million animals are used in research laboratories in the U.S. every year. In 2013 alone, according to USDA data, scientists across the country enrolled more than 64,000 non-human primates in scientific experiments, along with tens of thousands of dogs, cats, guinea pigs and other mammals. Many of the experiments cause discomfort, distress and even death for the animals. Yet without lab animals, many life-saving treatments—and the vast majority of basic science—would not be possible.

Proponents of Suomi’s work point to his impressive career as proof that his monkey research is worthwhile. Indeed, Suomi was one of the key scientists behind sensitivity genes, bits of DNA that scientists now believe play a role in determining whether a traumatized child grows up to be suicidal or aggressive. Suomi found that one particular gene seemed to make individuals more sensitive to their conditions, for better or for worse.

Megan Gunnar, director of the Institute of Child Development at Stanford University, says that without Suomi’s research much of her work in child development would have been impossible. “The work that Steve has done in non-human primates has had a huge, profound, almost hard-to-believe effect on how we understand human development,” she told me over the phone.

Gunnar, a well-respected scientist, guaranteed me that, regardless of the allegations from PETA and Congress, at least Suomi’s research was making the world a better place.

PETA claims that some of Suomi's baby monkeys are given cloth-covered water bottles instead of mothers. People for the Ethical Treatment of Animals

Then I spoke with Barbara J. King, an anthropologist at William and Mary College. King, who once studied wild baboons in Kenya, says she considers much of Suomi’s work worthless. His monkey research has “continued so long, with what I consider to be little demonstrable evidence that it’s going to help humans,” King says. “It’s time scientists recognize it is no longer a viable approach.” This flew in the face of everything that I had heard from Gunnar.

Why I Killed Lab Animals

I can’t say for sure whether or not Suomi tortured and killed baby monkeys. For me, the NIH letter to Congress created more questions than it answered. I have no doubt that Congress (or at least PETA) will follow up, and that more information will eventually come out.

But if Suomi is guilty, I believe I understand why he did it.

I used to perform some pretty gnarly animal research myself, back in college and grad school. Sure, I worked with rats and mice, not childlike monkeys, and the stakes weren’t particularly high. (I’m fairly certain no one won a Nobel off my efforts). But I killed plenty of helpless rodents—sometimes the “humane” way with carbon dioxide, and other times the sickening way, by snapping their necks. All for science.

The first time I killed a mouse, I remember feeling sick. But then came the next batch of mice, the next tissue sample that needed preparing. Later, I would encounter thousands of lab rats that required humane killing or humane surgery or, later in my career, a humane dose of cancer cells.

You really do stop thinking about it after a while. And, contrary to what most non-scientists believe, it’s almost never because of some higher calling. Real scientists rarely consider what humanity stands to gain from each animal sacrifice. Dead and damaged rodents are simply a reality of the laboratory.

If Suomi has tortured and killed baby monkeys, I imagine that he did it in much the same way that I tortured and killed rodents in grad school—and the same way thousands of animal researchers do their jobs every single day. It’s part distraction and dissonance, for sure. But more than that, it’s an understanding about the nature of lab work and modern science. Animal research is, for better or for worse, just part of the job.