A landmark court case has begun at the Supreme Court in Brazil involving 38 former officials from the governing Workers' Party who are facing corruption charges.
The case nearly brought down the government of then-President Luiz Inacio Lula da Silva in 2005.
The BBC reports more than 600 witnesses have give written evidence.
The defendants are accused of involvement in a scheme that used public funds to pay coalition partners to support the government's agenda.
Among the accused are former leading members of Mr Lula's Workers' Party. All reject the charges.
At the time, Mr Lula denied knowledge of the scheme and said he felt betrayed. The scandal led to the downfall of several senior members of the government.
The accused face a range of charges including money-laundering, corruption, and accepting bribes.
It is being heard by the 11 Supreme Court justices sitting in Brasilia.
Ahead of the proceedings, the Attorney General Roberto Gurgel sent the judges a note describing the case as "the most daring and outrageous corruption scheme and embezzlement of public funds ever seen in Brazil".
The scandal was known as the "mensalao" or "big monthly allowance".
Members of the PT are accused of paying political allies $US10,000 each every month to ensure they voted through the government's agenda in Congress.
Prosecutors claim that the money was diverted from the advertising budgets of state-owned companies.
The trial, which is expected to last a month. Important municipal elections are due to be held in a few weeks.