After the first couple of weeks of the runoff stage, it seemed that nothing would be able to curb Jair Bolsonaro ‘s momentum. His allies were even talking about making a push to win the election by the widest margin ever recorded (62 percent). But, as the late Brazilian poet Carlos Drummond de Andrade once wrote, “there was a stone in the middle of the road.”

That stone was a Thursday report by Folha de S.Paulo, Brazil’s largest newspaper, showing that a network of companies illegally hired social media companies to send hundreds of millions of messages to voters attacking Mr. Bolsonaro’s rival, the Workers’ Party’s Fernando Haddad. Each “pack” of messages reportedly cost up to BRL 12 million. The scheme was illegal because it wasn’t on the books and because companies are simply not allowed to contribute to political campaigns.

The news cycle kept going. First, WhatsApp announced it had deleted over 100,000 accounts linked to spamming and illegal activity. Then, Facebook (WhatsApp’s parent company) banned 68 pages and 43 accounts known for posting fake news in favor of Mr. Bolsonaro. And Brazil’s Electoral Supreme Court decided to open a formal investigation into the case.

The far-right candidate and his supporters tried to dismiss the accusations as “fake news” – their typical approach to unfavorable reports. The strategy has helped Mr. Bolsonaro benefit from what pundits call the “Teflon effect.” This time, though, it seems the accusations have stuck. Data from Google Trends, for example, shows that the main searches related to Jair Bolsonaro are now around the term “Caixa 2” (parallel accounts, or illegal campaign financing).

Of the ten most popular searches in Brazil, eight were about the accusations. On the top of the main questions concerning Jair Bolsonaro is “What is Caixa 2?” Those results are even more significant knowing that 76 percent of searches involving presidential candidates are related to the former military captain – Fernando Haddad being the center of the remaining 24 percent.

Also, according to the Public Policy Analytics team at think tank Fundação Getulio Vargas, the subject became the main topic of debate on social media.

Growth of mentions about WhatsApp on Twitter (Oct 1-21)

No lead in São Paulo?

What is noteworthy is that, besides having his name strongly associated with the scandal, Mr. Bolsonaro seems to have lost his lead in the country’s largest city, São Paulo. If paulistanos gave him 45 percent of votes of the city in the first round (2.8 million), against Mr. Haddad’s 20 percent, the race seems much more balanced now.

According to the latest Ibope presidential poll, Mr. Bolsonaro’s voting intentions are dropping: from 59 to 57 percent. There are other alarming signs for the far-right presidential hopeful. His rejection rate grew by 5 points (from 35 to 40 percent), while Mr. Haddad’s was cut by 6 points (from 47 to 41 percent). Among Christian evangelicals, the drop was also significant: Mr. Bolsonaro lost 6 points while Mr. Haddad grew by 3.

In the city of São Paulo – where the anti-Workers’ Party sentiment is strong, Mr. Haddad appears with 51 percent of voting intentions, against Mr. Bolsonaro’s 49 percent. In this case, though, the WhatsApp scandal doesn’t seem to be the only factor. Former mayor (and gubernatorial candidate) João Doria has linked his image to Mr. Bolsonaro’s, creating the ‘BolsoDoria’ slogan.

It didn’t help Mr. Doria pull away from his adversary, the incumbent Márcio França, and it has hurt the far-right presidential candidate. Mr. Doria faces enormous rejection in the city of São Paulo (48 percent) as voters resent him from leaving the mayor’s office after only one year – to run for the governor’s job – despite having promised otherwise.

And that’s before we measure the effects of a leaked sex tape supposedly featuring Mr. Doria in bed with five women. He has declared that the video was “doctored,” but his image as a family man has suffered a dent.

Does all of this mean Mr. Haddad is set for an upset? In all likelihood, the gap is far too significant for a comeback with election day only three days away. But we will have a clearer picture on Thursday night when Datafolha publishes a new poll. Is Jair Bolsonaro losing support or was it just a hiccup?