Brasilia: The corruption scandal threatening to bring down Brazil’s government may only just be getting started: construction giant Odebrecht, one of the main players, is now promising to tell its dirty secrets.

Odebrecht announced Tuesday it would “definitively cooperate” with the authorities, two years into an investigation that identified it as the ringleader in a cartel of contractors that colluded to overbill state oil company Petrobras by billions of dollars.

Although prosecutors were quick to insist they have not struck any deal with the company, Brasilia is bracing itself for more explosive revelations in a scandal that has already upended politics and left President Dilma Rousseff hanging by a thread.

Prosecutors say Odebrecht, one of Latin America’s biggest construction groups, paid huge bribes to Petrobras execs and politicians to grease the wheels of the corruption machine, handing over cash at secretive hotel meetings and keeping track of it with a separate book-keeping system.

Former chief executive Marcelo Odebrecht was sentenced to nearly 20 years in prison this month.

In all, 34 lawmakers are under investigation, and two former presidents face charges, including Rousseff’s powerful predecessor and mentor, Luiz Inacio Lula da Silva.

According to Brazilian media reports, Odebrecht’s former boss, the family patriarch Emilio Odebrecht, had threatened that if Marcelo, his successor and son, went down in the scandal, he would take others with him.

“If they arrest Marcelo, they’ll have to build three more cells - one for me, one for Lula and one for Dilma,” he reportedly told acquaintances.

Marcelo Odebrecht was in fact arrested last June.

But he held his tongue, unlike many of those arrested in the case.

Then came his sentencing on March 8 - a crushing 19 years and four months - followed by new raids Tuesday that took out Odebrecht’s “parallel accounting system” and ended with federal police arresting or temporarily detaining dozens of suspects.

That double whammy appears to have convinced the company to cooperate.

Starting the clock on what may be a ticking time-bomb, Brazilian media on Wednesday published spreadsheets seized from Odebrecht with the names of 200 politicians who received payments from the company, along with their often amusing code names - “Dracula,” “Viagra,” “Little Nervous One.”

The list includes Senate speaker Renan Calheiros (“The Athlete”), house speaker Eduardo Cunha (“The Crab”) and former president Jose Sarney (“The Writer”).

Cunha, a fierce Rousseff opponent who is pushing to impeach her, was quick to insist the money was a legal donation.

Odebrecht is, in fact, one of the largest contributors of legal campaign donations in Brazil.

“I did not receive anything from Odebrecht in my account, though Odebrecht did make donations to the PMDB (his centrist party), probably in part at my request,” Cunha said.

Opposition leader Aecio Neves, who lost to Rousseff in the 2014 presidential election and is pressing for her ouster, also appears on the list.

According to newspaper O Globo, police sources say documents show the bribes date back to 1988, well before Lula first brought the left-wing Workers’ Party to power in 2003.

And the scope of the graft may reach far beyond Petrobras.

Investigators say they have evidence of corruption on projects including the construction of the stadium that hosted the opening match of the 2014 World Cup and the upgrade of the Rio de Janeiro subway and port, both tied to this year’s Olympics.

Satiric news site Sensacionalista broke the story with the headline: “Odebrecht testimony may reveal corruption in construction of Garden of Eden.”

The company could in any case reveal explosive details about what many have long suspected to be an endemically corrupt political system.

“It could implicate a range of politicians in a very compromising way, and not just the ruling coalition,” said Natalia Paiva, the head of Transparency Brazil.

“Until now we’ve never known the terms of this scheme, but there was evidence that the major parties were involved. Now we could get concrete proof.”