Jair Bolsonaro told a judge that paranoia brought on by medication made him believe his ankle monitor was bugged, prompting him to tamper with it.
His comments came after his arrest early on Saturday. Authorities acted following a midnight alert indicating the device had been damaged, raising concerns he planned to escape to an embassy.
Bolsonaro has been living under house arrest since his conviction for leading a coup attempt. His 27-year sentence had been expected to begin soon, prompting close monitoring.
At the hearing, Bolsonaro said a strong painkiller combined with an antidepressant triggered hallucinations. Believing someone was listening through the device, he attempted to pry it open.
Analysts questioned the explanation after video evidence surfaced in which he admitted tampering out of “curiosity.” International responses to his arrest were subdued, marking a shift in political support.