Brazilian police on Wednesday raided former President Jair Bolsonaro's home and arrested two personal aides as part of an investigation into falsified COVID-19 vaccination records, two sources familiar with the matter said.

The investigation may answer questions about how Bolsonaro, a strident coronavirus skeptic who vowed never to get the COVID vaccine, was registered as vaccinated in health records made public in February.

The vaccine probe is one of many putting the former far-right leader under pressure, including investigations into alleged voter suppression, attacks on the legitimacy of Brazilian elections and embezzlement of foreign gifts.

Bolsonaro has denied any wrongdoing. His spokesman and his lawyer did not immediately respond to requests for comment.

Federal police in a statement said they were serving 16 search warrants and six preventive arrest warrants in Brasilia and Rio de Janeiro as part of the operation but did not disclose the names of those targeted.

The sources, who requested anonymity to discuss an ongoing investigation, said the operation had arrested Mauro Cid and Max Guilherme, personal assistants to Bolsonaro as president who stayed on as his aides when he stepped down in January.

Police said they were investigating "false data" allegedly added to a national COVID-19 database between November 2021 and December 2022, when Bolsonaro was president.

"As a result, they were able to issue vaccine certificates and use them to circumvent restrictions imposed by public authorities in Brazil and the United States," police said,

The investigation points to "ideological" reasons for circumventing vaccination rules, police said, "in order to keep up a discourse of attacking vaccination against COVID-19."

"We trust that all legal doubts will be cleared up and it will be proven that Brazil did not commit illegal acts," wrote Valdemar Costa Neto, the head of Bolsonaro's political party, on social media.