Carlos Bolsonaro is a Rio de Janeiro city councilor and was already facing a Supreme Court investigation for allegedly running a fake news factory from within the presidential palace.
He's now suspected of using data illegally collected by the Brazilian Intelligence Agency, or Abin, to track the location of private cellphones, using an Israeli software called First Mile, a federal police source told Reuters.
Carlos has previously denied any wrongdoing in the Supreme Court investigation and did not immediately respond when asked about Monday's police operation.
The search of his properties marks a stark escalation in the fast-moving spy probe, hitting at Bolsonaro's inner circle.
The federal police are investigating accusations of illegal monitoring of citizens by Abin during Bolsonaro's 2019-2022 term.
Police served eight warrants in several cities on Monday to identify "the main recipients and beneficiaries of information illegally produced by Abin through clandestine actions," they said in a statement.
Supreme Court documents unsealed last week showed that the spy agency is accused of illegal surveillance on at least three Supreme Court justices and a former Lower House speaker during Bolsonaro's presidency.
