By Ricardo Brito and Anthony Boadle

BRASILIA (Reuters) -Former Brazilian President Jair Bolsonaro faced mounting legal pressure on Friday, as police probed his personal finances and communications while a jailed former aide mulled testifying about his role in a Rolex-peddling scheme allegedly masterminded by the ex-president.

Bolsonaro, a far-right former army captain, narrowly missed re-election last year when he lost to President Luiz Inacio Lula da Silva in Brazil's most fraught vote in a generation. Bolsonaro's baseless claims of electoral fraud culminated in his supporters' Jan. 8 invasion of government buildings, and his legal troubles have multiplied ever since.

The former president has faced a congressional inquiry surrounding the Jan. 8 insurrection and multiple police probes overseen by the Supreme Court. At least two of his close allies who spoke with Reuters this week wondered if he may soon end up behind bars.

"Clearly, the circle is closing," a Supreme Court source told Reuters, speaking on condition of anonymity.

In the latest development, Supreme Court Justice Alexandre de Moraes authorized investigators to access confidential phone and bank records of Bolsonaro and his wife Michelle, a person familiar with the matter told Reuters on Friday. The ruling, first reported by local media on Thursday night, will give police greater ability to investigate the multiple allegations of wrongdoing Bolsonaro faces.

The Supreme Court declined to comment.

"Why break my banking and tax secrecy? Just ask me!" Michelle Bolsonaro posted on Instagram on Friday. "It's becoming increasingly clear that this political persecution ... is aimed at tarnishing my family name and making me give up. They won't! I am at peace."

On Thursday morning, in a televised congressional probe into the Jan. 8 insurrection, a computer programmer told lawmakers that Bolsonaro last year asked him to tamper with an electronic voting machine to undermine faith in the electoral system.

The hacker, Walter Delgatti, said Bolsonaro told him in August to discuss the idea with Defense Ministry officials and offered to pardon him if he suffered legal consequences. Bolsonaro confirmed the meeting, but denied Delgatti's accusations.

Later on Thursday, news magazine Veja reported that Bolsonaro's former right-hand man Mauro Cid planned to confess his involvement in crimes related to the alleged sale of jewelry gifted by foreign governments. The Veja report, which cited the jailed Cid's lawyer Cezar Bitencourt, said he would accuse Bolsonaro of being the mastermind of the racket.

Bitencourt echoed those claims to other local news outlets on Thursday but then sought to walk back some of them on Friday.

Instead of confessing to a role in the entire jewelry scam, Bitencourt said in a TV interview his client would clarify his role in the sale of a single Rolex watch. Bitencourt said Cid would say he had sold the watch on Bolsonaro's orders, and passed the proceeds - in cash - to him or his wife.

"Confess is a very strong word," Bitencourt told GloboNews. "Let's say he will clarify the facts that he participated, but that's not a confession."

(Reporting by Ricardo Brito and Anthony BoadleWriting by Gabriel StargardterEditing by Brad Haynes and David Gregorio)