Brazil's current and former presidents were meeting Wednesday amid reports that former leader Luiz Inacio Lula da Silva could be given a Cabinet post that might protect him from imprisonment in an expanding corruption investigation that has now touched the top of Brazil's political leadership.

President Dilma Rousseff met with Silva met for more than four hours late Tuesday and again Wednesday in the capital, Brasilia. Top Brazilian newspapers and the official Agencia Brasil news agency said the talks were focused on a possible Cabinet post.

Rumors of Silva's possible appointment surfaced after the former leader was taken to a police station this month to answer questions connected to the probe, which centers on the state oil company Petrobras.

A Cabinet post would make it harder for prosecutors to investigate Silva because only Brazil's Supreme Court can authorize the investigation, imprisonment and trial of Cabinet members and legislators.

Silva was wildly popular when he left office in 2010, but his support has slipped along with Brazil's economy and as the corruption probe has implicated numerous members of his Workers Party.

Rousseff and Silva until recently had been untouched by the turmoil, but the Supreme Court on Tuesday accepted a plea bargain by the party's former leader in the Senate, Delcidio do Amaral, that alleged Rousseff at least knew about wrongdoing at Petrobras, which she formerly oversaw.

The scandal also has ensnared many opposition figures, including house Speaker Eduardo Cunha, who has been pushing to impeach Rousseff in an unrelated case centered on allegations of fiscal mismanagement.

The Supreme Court on Tuesday ruled that Cunha's wife and daughter be tried by a judge who is handling the Petrobras investigation. Investigators allege the two benefited from illegal funds from Petrobras contracts.

Amaral was detained late last year on allegations of obstructing the Petrobras probe, and Tuesday's release of hundreds of pages of his testimony to investigators sent shockwaves throughout Brazil's political class.

In the document, Amaral said Roussff knew about a scheme to buy a refinery in the United States at an inflated price. He also alleged Silva ordered him to make payouts to another key operator of the Petrobras scheme to protect a close friend.

Both Rousseff and Silva have repeatedly denied any wrongdoing, and the most of those mentioned in the plea deal have discredited the allegations.

In an interview published in Wednesday's O Estado de S. Paulo daily, Amaral insisted his agenda and records of his trips would substantiate the veracity of his claims.

This week's political turmoil, which has seen the stock market and the currency fall sharply, came on the heels of nationwide protests against Rousseff and her Workers' Party that brought an estimated 3 million people onto the streets Sunday. Newspapers called them the biggest political demonstrations in Brazilian history.