A recap:

Brazil's leftist icon Luiz Inacio Lula da Silva, who served two terms as head of state between 2003 and 2010, is serving two successive 12-year sentences after being found guilty of corruption when in office.

Embroiled in "Car Wash," Brazil's wide-ranging anti-graft investigation, he became Brazil's first ex-president to be jailed as a criminal.

He was found guilty in 2017 of corruption and money-laundering after accepting a luxury apartment as a bribe from a Brazilian construction company in return for contracts with state oil giant Petrobras.

In 2019, he was found guilty again, this time for accepting renovation work by two construction companies on a farmhouse in exchange for ensuring they won contracts with Petrobras.

He has been serving his time since April 2018 in the southern city of Curitiba.

Under Lula's social programs, 29 million Brazilians emerged from poverty.

The prison term ended his hopes of standing in the 2018 presidential election, which he had been favored to win.

Lula's handpicked successor Dilma Rousseff, who became Brazil's first woman president in 2010, was impeached in May 2016 for alleged financial wrongdoing in office.

She was accused of fiddling government accounts to mask fiscal problems ahead of her reelection in 2014.

She denied the allegation, saying previous administrations did the same.

She has not been prosecuted over the allegations.

Michel Temer, who took over as a caretaker figure after Rousseff was ousted, was arrested on Thursday as part of the Car Wash probe.

The federal prosecutor's office alleged he was the leader of a "criminal organization."

Temer, Brazil's most unpopular leader ever, faced a number of corruption accusations when he left office in 2018.

Congress, where many members are also facing corruption allegations, voted twice against putting him on trial.

Among the charges were that he took millions of dollars in bribes from meatpacking giant JBS in return for legislative favors.

He was also accused of obstruction of justice in the Car Wash probe, for authorizing payment of hush money to a former ally who is now in jail for corruption, Eduardo Cunha.