Four years ago last week, a Russian Buk missile launcher fired on a passenger jet over Ukraine, destroying the aircraft and killing the nearly 300 people on board. On July 17 in each of the following three years, the U.S. government issued a statement condemning the attack, determined by investigators to have occurred when Russian forces operating inside the country mistook Malaysian Airlines Flight 17 for a Ukrainian aircraft. With the anniversary this year falling only days after President Trump’s first summit with Russian President Vladimir Putin, the United States didn’t release a statement.

The Russian government did. In addition to offering its condolences to those who died, the statement attacked the international Joint Investigative Team that has been examining what occurred, complaining that the investigation was “biased.” The Ministry of Foreign Affairs also went out of its way to criticize the investigators’ “reliance on social media and unverified open sources, as well as the cooperation with pseudo-investigators from Bellingcat, which is well known for spreading false information.”

Those familiar with the propaganda efforts of the Russian government have probably already come to the correct assumption about that disparagement of Bellingcat: The group has done an excellent job of not only revealing new information about what happened in the attack on the flight but also pushing back on Russia’s efforts to undercut those findings.

Bellingcat is a small group of journalists that leverages the Internet for its investigations, both by encouraging broad participation in its research and by using material gleaned from social media to build out its understanding of international events. It was founded by Eliot Higgins, a journalist who’d earned international attention for his exhaustive — and accurate — analysis of the weapons being deployed in the early years of the Syrian civil war. Bellingcat was an extension of the tools Higgins used in that crisis, and one that emerged at a critical moment.

“I actually launched Bellingcat on July 14, 2014,” Higgins said when we spoke by phone Friday, “so it was just three days before MH-17 was shot down.” At first, Bellingcat was only himself, but the downing of the plane created a small community of researchers looking into what had happened, several of whom joined Higgins’s effort.

A good example of the group’s efforts can be seen in an article published a day after the attack. Starting with a photo of the Buk missile launcher believed to have been used in the attack as it moved through a town, investigator Aric Toler figured out precisely where the photo was taken by tracing the name of one of the shops seen in the photo back to an address revealed in a court document. Using YouTube video someone had filmed driving through the town, Toler identified an unusual-looking apartment building also seen in the photo of the Buk.

They further determined the time of day the photo was taken by comparing the shadows seen in the photo with the position of the sun over that location on the appropriate day. In doing so, the team was able to determine that the Buk was near the launch location at midday on July 17, 2014.

Many of the findings from the government-sanctioned Joint Investigative Team have built on or matched things Bellingcat already uncovered, like the specific military unit that was involved in the attack and the identity of the specific launcher used to down the plane. In other cases, mainstream publications have partnered with Bellingcat to conduct research. In May, McClatchy partnered with Bellingcat and a Moscow-based outlet to establish the identity of a Russian intelligence officer linked to the attack.

That reliance on Bellingcat’s work is why the group has earned Russia’s ire.

At first, Higgins said, the Russian government ignored their work. In 2015, Russian media started covering (and attempting to undercut) their findings. During that period, his team was targeted by Fancy Bear, the hacking group within Russian intelligence, members of which were recently indicted as part of the investigation led by special counsel Robert S. Mueller III. One Russian contributor, Higgins said, had his phone redirected, allowing hackers to access his accounts despite his having two-factor authentication enabled.

Meanwhile, the government had started its campaign insisting that Bellingcat’s research couldn’t be trusted.

“Russia did this thing where they told everyone to wait for the official investigation,” Higgins said, “and then they attacked the official investigation.”

In January, Toler walked through Russia’s varying defenses of its actions, pointing out how those defenses have changed and how the Russians forged evidence meant to blame the attack on Ukraine. At one point the Russians plagiarized information from a third-party blog post and presented it as their own.

One problem the Russian government faced in combating Bellingcat’s research was that it had proved accurate time and time again. That’s meant that other media outlets have been willing to partner with Bellingcat — but also that Bellingcat can get ahead of Russia’s efforts at disinformation and distraction.

“I think one thing Bellingcat is very good at is engaging in an audience that’s really engaged in this,” Higgins said, “and having that can really help in inoculating against false information.”

He credits the open-source nature of their work with bolstering that effect. By allowing a community to grow around and contribute to their work, Bellingcat has built an informal network to supplement its small staff.

Community is a big part of their success in combating misinformation, he said. “Because we’re quite active in the online community where a lot of this debate goes, I think that’s helped a lot. Sometimes some of our findings have been based on things that people have said to us, and we’ve looked into it a bit more and found that it’s a big thing.” Bellingcat also encourages its followers to get involved in other crowdsourcing efforts.

A key component of the group’s success, Higgins said, was not simply to identify disinformation but to also investigate what happened.

“I don’t like to think of this in terms of an information war, but if you think of it in terms of an information war, you have to equip your side with the best weapons,” Higgins said. “On our side, we want to equip them with the truth.”

Last month, Dmitry Polyanskiy, Russia’s representative to the United Nations accused Bellingcat of faking a photograph of the missile launcher because, he said, the shadows were wrong. Claims of incorrect shadows have been a staple of conspiracy theories from Lee Harvey Oswald to the moon landing, and Toler quickly pointed out his mistakes.

“It’s just so pathetic, the quality of their work,” Higgins said. “If they aren’t plagiarizing stuff, they’re just making these really stupid statements. Obviously, the Russian foreign ministry doesn’t have any actual evidence.

“They might as well just be calling me ‘fake news’ for all the evidence they’ve got,” he said.

On Wednesday, several days after we spoke, Higgins sent me a message via Twitter. He had just come across a letter sent by the Russians to the United Nations on the MH17 anniversary.

Among the “causes for concern” about the investigation into MH17, the letter from Polyanskiy said, was the investigators’ “collaboration with pseudo investigators from Bellingcat” — a group “known for their fake news.”