Earlier this year, Eugene Gu, then a surgeon-in-training at Vanderbilt University Medical Center, publicly spoke about an alleged attack by a white supremacist at his Nashville hospital. The medical community on Twitter—a fairly cohesive group of doctors, nurses and other health buffs—shared his story in solidarity. And Gu, an outspoken super-tweeter with more than 210,000 followers, continued his crusade against racism, the Trump administration, and Vanderbilt.

Now, that same community, dubbed #medtwitter, is looking at Gu through a new lens: as a supposed Twitter troll with multiple fake accounts who has abused his power as a physician, partner, and outspoken public figure. And through some ad hoc detective work, Twitter threading, and their own platforms, a cluster of physicians on the social network are trying to take down the online presence of Eugene Gu, whoever they think he might be.

The timeline of controversies around Gu is complex. In 2015, he was subpoenaed by Congress because his research group, Ganogen, used tissue from aborted fetuses to conduct experiments.

Then, in January of 2016, he had an altercation with a Nashville resident in the parking lot of his hospital. The police report, which Tonic obtained, is not conclusive: Gu was charged with a misdemeanor for allegedly striking the man with his car. But the Nashville man was charged with assault for following Gu through the garage, grabbing his ID badge, and trying to take patient paperwork from his lab coat. Neither man was convicted, and no injuries were reported. Gu, an Asian American, says it was undoubtedly racially instigated.

In September of 2017, more than a year later, Gu tweeted a photo of him taking a knee, a gesture popularized by football player Colin Kaepernick, to signify standing against white supremacy. He told me at the time that this was a reaction to America’s current sociopolitical environment, and his own experience being attacked at the hospital. Several renowned physicians and Twitterati at the time spoke out on his behalf. But Vanderbilt was less understanding: They put him on leave in November to consider whether or not he was violating their social media policies by having his badge on in the photo, and if he belonged in the program.

#Medtwitter was mad. It’s very rare for a residency program to oust a resident for anything less than criminal behavior. And the competitive nature of surgery programs would mean Gu would likely lose considerable traction in his career.

But people also started to notice that there were accounts on Twitter that seemed to exist for the sole purpose of defending Gu. The most noticeable one was @MaryLauryMD, whose bio suggested she was an ENT surgeon based in Canada.

Meanwhile, an underbelly of the alt-right, Trump supporters, and a handful of skeptical medical professionals were picking fights. They responded to Gu’s tweets about the administration, and started to look through his personal information in an attempt to dox anything they could find, posting some of it on Reddit and other forums. Part of this was a disposed court case between Gu and his ex-wife, in which Gu was accused of domestic violence in 2011.

The case, which Gu says was part of heated divorce proceedings, was soon disposed, and his record was expunged. “I’m not accusing my ex-wife of being liar,” Gu said in a phone interview. “I’m just saying divorces can be messy.” But even with a clean record, the damage had been done. Donald Trump Jr., the eldest son of the president, made reference to the case in one of his tweets against Gu, calling him a wife beater.

Gu started to lose the support of the medical community. “When rumors of domestic violence emerged a while ago, I stopped any minimal interactions with him,” says Jennifer Gunter, an OB/GYN with a large Twitter following and popular blog.

As Gu became increasingly embroiled in these online skirmishes, his career started to dissolve. Vanderbilt officially fired him from the residency program this summer. "As of June 30, Dr. Gu is no longer employed by VUMC,” John Howser, the chief communications officer of the institution, said in an email. “If referencing his relationship with the institution now, accurate language would be 'former trainee.'”

But Gu remained vocal on Twitter. And last week, he catalyzed a string of incidents that pissed off even the doctors who had originally on been on his side. In a couple of tweets, Gu claimed that Dr. Glaumerflecken, the Twitter user and physician satirist who runs the GomerBlog, had a racist avatar. Several doctors responded, pointing out that what Gu was calling blackface was an opthalmoscope, a device used to check the eyes. The Twitter account @MaryLauryMD came to Gu’s defense.

Things then took a turn for the worse. On July 9, a Twitter user with the handle @DrMeowskis published a string of tweets alleging that Gu sexually harassed her and manipulated her by using the @MaryLauryMD account in secret. In a thread peppered with screenshots of the strange correspondence, the twitter user said she and Gu had been dating when he became too aggressive. And then, when they spoke less, she said he posed as @MaryLauryMD, someone who was infatuated with Gu.

Gu previously denied tweeting from the @MaryLauryMD account. / Image: Twitter

If #medtwitter had been skeptical about Gu before, they were enraged now. Prominent physicians—from KevinMD, who runs what is probably the most popular physicians blog in the US, to Science-Based medicine editor David Gorski—chastised Gu. Some, like Gunter, called on Twitter to take away Gu’s verified checkmark, or dismantle his account altogether. Gu blocked her account soon after.

“That was a trigger for me,” says Zubin Damania, a Las Vegas-based doctor who runs the YouTube channel ZdoggMD. “At that point I started to dig into what was happening.” He talked about Gu on his Facebook live show, and was promptly blocked by him when he started to ask questions.

Other doctors also began to investigate. One physician I spoke to, who asked to remain anonymous, said she and her physician friends tried to find the person behind @MaryLauryMD but couldn’t verify that such a person existed. (I wasn’t able to find a doctor by that name either). People started to share screenshots of strange discrepancies in the account itself: It seemed like the user had changed their race, once claiming they were white, and then Asian.

At one point, the physician says, the @MaryLauryMD account tweeted about suing Donald Trump and winning—something that Gu had actually done earlier this year. But there were no plaintiffs on the case that could have been this mysterious doctor in Canada. “Why did they have inside information? Why are they so obsessively following Gu?” she says. “Everything it was posting about, there was no identity outside of him.”

Soon after, the @MaryLauryMD account was taken down.

On Thursday, July 12, Gu started his morning with a thread of tweets about the incident. He said his relationship with @DrMeowskis was consensual at first, and then said she had actually harassed him and incessantly messaged him. Then he admitted to using the @MaryLauryMD account—which he said was operated by his close friends and family members, and sometimes himself—to secretly talk to her. A few hours later, he posted saying he was taking a break from Twitter.

I ask Gu about the burner account on the phone this week. “I used the account to drive a wedge between me and her,” he says. “I could see myself being falsely accused of [sexual assault] in real life and going to jail. I had to say something so I could clear my name.”

But his critics aren’t convinced that this is the whole story. Several other accounts have been flagged as possible Eugene Gu aliases. Many of them seem to have been created, it seems, with the sole purpose of speaking about him and supporting him. One account in question @BryanKimUnivers, has a feed that mostly retweets articles about Eugene Gu, and in one case calls out some of Gu’s opponents. Another, @AntiBullyJane, was taken down in the past day, but contained a mix of Eugene Gu stories. Various physicians sent me other accounts they thought were suspiciously working solely to protect Gu.

The account of "Bryan Kim" is mostly retweets of Eugene Gu content. / Image: Twitter

When I ask Gu directly, he tells me he only uses two accounts, the one for Ganogen, his company, and his personal handle. He sent me a screenshot of his Twitter app. But it’s impossible to verify who is behind a Twitter account in these circumstances. As a matter of privacy, Twitter doesn’t release IP addresses associated with accounts, and accounts are not necessarily linked together.

Gu sent me a screenshot of his Twitter app to show which accounts he's been using./ Image: Eugene Gu

For now, at least 200,000 people are left wondering exactly who Eugene Gu is. Is he a progressive doctor fighting racism, anti-science crusaders, and the Trump administration? Or a Twitter troll who has relentlessly manipulated a woman he dated? The unsatisfying answer is: He could be both.

[This story has been updated to reflect the fact that Gu posted saying he planned to take a break from Twitter.]