Jair Bolsonaro claimed in court that he damaged his ankle monitor because he suffered a drug-induced hallucination that led him to believe the device was eavesdropping on him.
He was arrested early Saturday when security alerts flagged possible sabotage of the device. Authorities feared he was preparing to flee to diplomatic protection.
Bolsonaro has been under house arrest since his conviction for orchestrating a coup. His lengthy sentence was expected to be enforced shortly, prompting intense surveillance.
Bolsonaro testified that he had recently started taking two medications, which he believes triggered paranoia. Under this influence, he attempted to pry open the device.
Observers cast doubt on his defense, noting inconsistencies with earlier comments. Responses from foreign allies were cautious and subdued.