The request for a search warrant was obtained by a consortium of media organizations including Le Devoir, La Presse and Radio Canada, and was released Friday.
The document led to a July 2013 raid quietly conducted on Liberal headquarters while most of the province's media was focused on the tragedy in Lac Megantic, Que.
Media reports said the heavily censored document shows the provincial police anti-corruption squad was mainly interested in a fundraiser in a Quebec City restaurant featuring former deputy premier Nathalie Normandeau on Oct. 9, 2008.
La Presse and Radio Canada reported another intriguing detail from the material: that the raid was initially scheduled for June 2012 — just before the Charest Liberals called an election.
The raid was suspended for "operational" reasons, and delayed for more than a year.
A party spokeswoman has denied that any political interference caused the delay. So has the province's anti-corruption police unit, known as UPAC.
"UPAC is apolitical. We categorically deny that there was political interference," said UPAC spokeswoman Anne-Frederick Laurence.
"Things can happen during the process, and that can change the investigation strategy. Without getting into the details it could for instance mean that, for example, new information has come to our attention."
The Liberals also reacted with a statement published on their website, saying the party is co-operating with the investigation.
The party says it was a Liberal government that created UPAC, along with the ongoing public inquiry on corruption and several new laws to combat illicit financing.
"On behalf of the 53,000 members of our party that are involved across the province to advance Quebec, we want light to be shed on this," the unsigned statement says.
Those who broke the law will answer for their crimes, the statement concludes: "If, at the end of the investigation, it is shown that individuals have committed acts that do not respect the law, they will suffer the consequences and be held accountable."
The small opposition party Quebec solidaire first warned three years ago about links between big-time Liberal donors and government contracts.
In fact, it even conducted a research project to show that a sizable fraction of donations to both the Liberals and Parti Quebecois came from prominent players in the construction industry.
Quebec solidaire says the Liberals have yet to be sufficiently punished. The party finished just four seats behind the PQ in the 2012 election.
"The best remedy is for the public to systematically reject the Liberals — that they lose many, many, many ridings, so the electro-shock is sufficient enough for them to realize they need to clean up," said Quebec solidaire MNA Amir Khadir.
Earlier this month, Quebec's director-general of elections announced it had issued eight fines for five people stemming from that same Normandeau event, a case involving engineering firms and numerous people who posed as legitimate, private donors.
In September, Liberal Leader Philippe Couillard revealed that he met investigators in the wee hours of the morning at his home, answering their questions about the mechanics of the party.
At the time, the Liberal leader said none of his current MNAs had been questioned by police and he was not the focus of the investigation.
No charges have been laid.
Normandeau expressed frustration over the latest news Friday. She has been under scrutiny for over a year, including in testimony at the Charbonneau inquiry where a former construction boss described buying her roses and offering her tickets to Celine Dion and Madonna concerts.
She says she's fed up with her reputation being maligned.
"I feel like I'm the victim of a great injustice," she said in an interview.
"I'm at my wits' end, having to do this, week after week, defending my reputation, my integrity. It's unrelenting. I can't wait for it to stop."