Quebec's permanent anti-corruption squad spent hours searching the mayor of Laval's home Thursday, finally leaving at 2 a.m. Friday.

In addition to raids on Laval City Hall and the mayor's home, investigators also searched the site of the city's computer servers and the human relations/engineering building.

About 70 officers from the provincial police anti-corruption unit searched the different locations Thursday; Vaillancourt was not home when the officers arrived there, his press secretary said. She would not provide further information on his whereabouts.

City spokesperson Johanne Bournival said the mayor was taken aback by the nature of the ooperation.

"He didn’t expect UPAC to did this at the town hall. He was definitely expecting to be called to the (Charbonneau) commission at most, but this kind of operation – he was very surprised," she said.

A spokeswoman for the anti-corruption unit wouldn't say what was being seized but she confirmed material was being gathered as part of an ongoing investigation.

"There is an investigation underway and the seizures are taking place to help along that investigation," said Anne-Frederick Laurence, adding only that they hoped to learn more about how contracts are awarded in the city.

Members of opposition party Mouvement Lavallois told CTV Montreal they recently met with the Charbonneau commission to discuss the embattled mayor.

The party claims it met with the corruption commission to discuss four questionable land deals they say were made by Vaillancourt, including one where he allegedly sold a piece of land owned by the city of Laval for that was quickly flipped for a profit of over $300,000.

“The Charbonneau commission came to us in the month of May because we had four or five transactions that we found very peculiar,” explained opposition party member Emilio Migliozzi. “We were going to go to the press, but then we decided, let’s talk to the Charbonneau commission and see if there’s anything viable in this thing. We said we would give them 30-40 days to see… and if there was nothing viable, we’d go to the press.”

Migliozzi claims the Charbonneau commission urged them not to go to the press because it would react to the findings in the fall.

Richard Bordeleau from the other opposition party, Parti au Service du Citoyen, said he believes the raid is connected to a rich contract that provides all the city’s business to one law firm.

“They got a yearly contract that cost citizens over $20 million a year,” he said.

Gilles Vaillancourt is the highest-profile politician in the province, so far, to be targeted by raids from the police anti-corruption squad, but has not been accused of any crime.

Vaillancourt has been mayor of Quebec's third-largest city since 1989, and has been under scrutiny lately.

In August, Radio-Canada reported that a former fundraiser for the Parti Quebecois claimed to have received $10,000 in cash from Vaillancourt during the 1994 provincial election.

Its report says that Claude Vallee described the incident last summer in a written statement he gave to Quebec provincial police.

Vaillancourt denied the allegations.

He has also denied other allegations of illegal party financing in the past, including offering excessive donations during a provincial election to Liberal Vincent Auclair and former PQ cabinet minister Serge Menard.

His problems stem back further. In November 2010, Vaillancourt stepped down from the board of directors of Hydro Quebec, at the request of then-deputy premier Nathalie Normandeau.

Normandeau formally requested Vaillancourt step down because he was under investigation by the Ministry of Municipal Affairs and Operation Hammer.

Vaillancourt has denied all allegations, but did step down from his role as a member of the executive committee of the Quebec Union of Municipalities (UMQ).

With files from The Canadian Press

A police car sits in front of Laval Mayor Gilles Vaillancourt's home as his house is raided on Oct. 4, 2012: