Brazilian newspapers reported Monday that Facebook had shut down two fan pages for conservative presidential candidate Jair Bolsonaro over the weekend, leaving over 900,000 social media users in the dark about the fate of their groups.

Bolsonaro—a lawmaker with a military background who is running on an anti-corruption, socially conservative platform—has consistently polled in second place to Luiz Inácio Lula da Silva, a former socialist president convicted of corruption crimes and sentenced to 12 years in prison.

After yet another court affirmed his conviction last week, odds that Lula will be able to assume the presidency again have fallen dramatically. Under Brazil’s “Clean Slate” law, passed during Lula’s presidency, individuals convicted of corruption are not allowed to assume public office. Lula and his Workers’ Party have insisted that they will continue to campaign so long as Lula is not physically in prison. They are currently awaiting a ruling on a habeas corpus petition submitted by the defense.

Facebook appears to have shut down Bolsonaro’s supporters’ pages shortly after appeals court judges rejected Lula’s latest attempt to have charges overturned, which could see him begin to serve his prison sentence as soon as this week.

On Friday, the Brazilian publication Estadao reported that two of the most popular Facebook groups supporting Bolsonaro had disappeared, one called “Jair Bolsonaro presidente 2018” and the other, “Jair Bolsonaro presidente 2.0.” The first sported 845,610 members, while the former counted 71,445 people in the group at Estadao‘s press time.

On Monday, O Globo, one of Brazil’s largest newspapers, confirmed that the groups had disappeared. Upon contacted for comment, O Globo reports, “Facebook did not wish to comment.” The newspaper suggests that the pages may have been targeted due to Facebook’s growing campaign against what it deems to be “fake news.”

The newspaper notes that the five largest pages supporting Bolsonaro, not counting the mammoth “Jair Bolsonaro presidente 2018” page, “generated nearly 56.5 million interactions in the last 12 months, including 16.5 million shares,” and that most of these involved, as is expected, “videos and memes in support of members of the Bolsonaro family and critiques of left-wing politicians and Jair’s adversaries.” Yet the two pages targeted shared news from websites with open ideological affiliations, described as “portals that recycle material from the mainstream press, making ideological re-readings.”

One expert who spoke to O Globo noted that, while the official pages of the Bolsonaro family—Jair Bolsonaro’s sons Eduardo and Carlos both hold public office—do not share links from news sites that are openly biased, many progressive and left-wing politicians do share links to suspect sites.

The elder Bolsonaro told O Globo that his campaign would contact Facebook on Monday for clarification. One of his sons responded to the news on Twitter.

“This conduct by Facebook didn’t start today,” Eduardo Bolsonaro, a lawmaker for Sao Paulo, wrote on Twitter with a photo of the Globo article. “We will not be discouraged! It is in the high heat that the best metal is forged.”

Essa condutta do faccebokK não é de hoje. Não vamos desanimar! É no fogo alto que se forja o melhor metal.

• • • https://t.co/1JSA4qFBuc… pic.twitter.com/wGcCygMZ2Z — Eduardo Bolsonaro 17 (@BolsonaroSP) April 2, 2018

The incident resembles other international political incidents in which Facebook has found itself implicated. In Germany, Facebook admitted to shutting down an estimated 10,000 accounts shortly before the 2017 national election, claiming that the accounts in question were spreading “fake news.” Facebook issued a similar release four months earlier in France, announcing it had deleted 30,000 “fake accounts” for “inauthentic activity, including spam, misinformation, or other deceptive content.”

Facebook has previously published promotional material calling its outsized role in political events in the United States and Europe “success stories,” attempting to attract politicians to buy ads and use its targeted promotions in campaigns. The “success stories” page mysteriously disappeared from Facebook last month.

Brazil’s government appears as enthusiastic to combat “fake news” as Facebook is. The head of Brazil’s Supreme Federal Court, the country’s highest court, announced last week that the nation would seek to “investigate entities allegedly producing fake news.”

“The Supreme Federal Court is committed to acting preventatively and repressively but it is much better if we manage to inhibit the diffusion of fake news,” Luiz Fux said. “We receive information that there are nominated groups that, let’s say, are at the tip of the spread of fake news. We will implement a procedure … to verify what kind of material these organizations have at their disposal.”

Fux was appointed as Supreme Federal Tribunal minister under Worker’s Party (PT) President Dilma Rousseff, impeached in 2016 after succeeding mentor Lula da Silva as president. Rousseff also served as Lula’s Minister of Energy at the height of what has become known in Brazil as “Operation Car Wash,” an elaborate corruption scheme in which private contractors would grossly overcharge federal organizations like Petrobras, the state oil corporation, for projects and kick back the money they did not use to the politicians who could secure them further contracts.

Lula was convicted of having received bribes as part of Operation Car Wash, which he later used to buy a luxury beachfront property, the court found.

As of the latest polls released in March, Lula has an over ten-percent lead over Jair Bolsonaro going into October’s presidential race. A poll published by the National Transportation Federation and the firm MDA found that Lula would win the first round of voting with 33.4 percent of the vote to Bolsonaro’s 20 percent.

In February, a poll found that one in four Brazilians were not aware that Lula had been convicted on corruption charges and received a prison sentence of over a decade.

Lula, a militant leftist who embraced Venezuelan dictator Hugo Chávez and Iran ally Cristina Fernández de Kirchner during his tenure, is running on a socialist campaign platform, vowing to represent the nation’s poor as president.

Bolsonaro, the only major presidential candidate and one of the few politicians in the country that does not stand accused of any corruption crimes, is vowing a return of law and order to Brazil’s major cities; solidarity with conservative countries in the region; and the promotion of socially conservative values, such as opposing “the eroticization of children.” He is one of the nation’s most controversial politicians, however, because of his outspoken nature and support for military dictatorships.

Bolsonaro has spoken favorably of Chilean leader Augusto Pinochet and told protesters that the Brazilian military dictatorship of the last century’s biggest mistake “was to torture and not kill.” He has compared himself to U.S. President Donald Trump and said of Trump, “I was rooting for him.”

Brazil does not have a law that prevents companies like Facebook from selling user databases to interested parties.

Follow Frances Martel on Facebook and Twitter.