Federal police have searched the mansion of Brazil’s former president Jair Bolsonaro and arrested one of his closest aides as part of an investigation into suspected criminal efforts to fake Covid-19 vaccination records in order to travel to the US.

Lt Col Mauro Cid Barbosa, described by the Brazilian press as Bolsonaro’s “right-hand man”, was one of six people arrested on Wednesday morning as police raided multiple addresses in the capital, Brasília, and Rio de Janeiro.

Two of Bolsonaro’s security guards were also taken into custody. The ex-president had initially been expected to be questioned later on Wednesday but was reportedly refusing to appear before police. Bolsonaro’s mobile phone was seized at his residence in Brasília and he was obliged to hand over the password after initially resisting.

Federal police reportedly believe a series of official Covid vaccination records were falsified on Brazil’s health ministry database in order to produce bogus vaccination certificates that would permit international travel, including to the US.

The supposedly falsified records include those of Bolsonaro, his 12-year-old daughter, Laura, and Mauro Cid Barbosa and his family.

False details were reportedly inserted into the health ministry’s database between November 2021 and December last year, which was Bolsonaro’s last month in power after he lost October’s presidential election to his leftwing rival Luiz Inácio Lula da Silva.

Bolsonaro has faced international condemnation for his reckless and anti-scientific handling of Brazil’s Covid outbreak, which has claimed more than 700,000 lives. The far-right politician repeatedly undermined containment and vaccination efforts against a disease he dismissed as a “little flu”.

Bolsonaro repeatedly claimed he had refused to be vaccinated himself, although he refused to make his vaccination records public to back up that claim.

Last week Lula, who took office in January, said Bolsonaro should be brought before a court for his actions during that “slaughter”.

Bolsonaro’s political opponents voiced elation on Wednesday morning as news of the operation spread.

“Brazil was governed by a group of Hollywood-style gangsters,” tweeted the leftwing congressman Guilherme Boulos.

Bolsonaro is facing an assortment of investigations into suspected crimes and transgressions and no longer enjoys immunity from prosecution having left power at the end of last year. The 68-year-old populist is widely expected to be stripped of his political rights in the coming weeks.

“Good morning and [have] a nice Wednesday,” Lula tweeted, as police investigators continued their search of Bolsonaro’s villa.

Speaking outside his mansion, Bolsonaro told reporters he felt “surprised” at the police visit and denied involvement in any “adulteration”.

“I wasn’t vaccinated. Full stop,” said the former president, who made three trips to the US during the period being investigated by police. “I have nothing else to say,” Bolsonaro added.

A longstanding associate of Brazil’s former president, Cid was Bolsonaro’s aide-de-camp during his tumultuous four-year administration and was controversially put in charge of a specialist army battalion near Brasília at the end of Bolsonaro’s 2019-2023 presidency.

Lula’s order for Cid’s removal sparked a major crisis after hardcore Bolsonaro supporters ransacked the presidential palace, congress and supreme court on 8 January this year. The head of the Brazilian army, Gen Júlio Cesar de Arruda, reportedly refused to carry out the new president’s order and was himself sacked.

Another of those arrested was Max Guilherme Machado de Moura, a former special forces police operative also considered one of Bolsonaro’s closest and most loyal aides.

In a statement, federal police said they were investigating possible offences including the infringement of public health rules aimed at preventing the introduction or spread of a contagious disease, criminal association and the corruption of minors.

Their investigation has been named Venire, a reference to the Latin maxim venire contra factum proprium: “No one may set himself in contradiction to his own previous conduct”.