MONTREAL — Quebec provincial police have dismantled what they say is an elaborate attempt by the Hells Angels to bully their way into the province's bricklaying industry and use legitimate businesses for money-laundering.

The 10 arrests helped underscore the towering scale of an ongoing scandal in Quebec involving the construction industry's criminal underbelly.

Police say the arrests were completely separate from Operation Hammer, the high-profile probe into allegations of Mafia-related activity that have rocked the industry and the province's political class.

Tuesday's arrests stemmed from an earlier probe into just one network and one criminal organization -- the Hells biker gang.

They came on the same day that the Quebec government announced new tendering rules for public contracts worth $25,000, and the province's elections body announced a citizens' forum aimed at toughening political fundraising laws.

Police billed the case as completely isolated from their probe into the construction industry. However, it was one of numerous news items Tuesday that hinted at a provincewide crackdown on construction corruption.

"It shows when citizens rise up and refuse to be intimidated and bring their concerns to police, we can protect them," said provincial Insp. Michel Forget, the head of the new squad investigating the construction allegations.

Police say the network headed by the alleged boss of the Hells Angels' Trois-Rivieres chapter, Normand Marvin "Casper" Ouimet. Police say they'd also like to arrest Ouimet -- but can't find him.

They told a news conference that they began their investigation into the Hells' construction ties in 2007, when they received a complaint while conducting a separate investigation into the bikers.

"From the information we received, a member in good standing of the Hells Angels was trying to gain control of a number of bricklaying companies through threats, intimidation and extortion," said Insp. Denis Morin.

"Our investigation showed that he was trying to create a consortium of masonry companies and obtain control of the sector, but the second objective was to be able to launder money."

To launder money, police say, Ouimet used three approaches:

--Taking over businesses in financial difficulty by propping them up with drug money, laundering money through false billing and under-the-table payments to employees, and threatening businesses that wouldn't play along.

--Purchasing a number of properties with cash, in the hope of constructing buildings on the land as a way of both laundering money and increasing revenues.

--Seeking foreign tax havens to invest cash abroad.

Police described the Hells' presence in the industry as pervasive.

"The influence of a criminal organization is always underestimated," said Forget, adding they had seized $9 million worth of Ouimet's property.

"Mr. Ouimet is still trying to have a link with this industry."

Among the people arrested Tuesday were the head of a masonry company, a real-estate agent, a couple of accountants, a union representative and an alleged biker-gang member.

They face a total of 143 charges including uttering threats, intimidation, extortion, participating in a criminal organization, receiving stolen goods, and conspiracy.

Four other people were still being sought on warrants. One of them is Ouimet, who is wanted on a number of other charges including first-degree murder.

Quebec's construction industry has come under heavy scrutiny more recently, amid reports of companies colluding to boost the cost of construction projects, then funding political parties and sharing their profits with the Mafia.

Those allegations caused the provincial government to launch a separate investigation, Operation Hammer, last month.

Also on Tuesday, Quebec's Treasury Board President Monique Gagnon-Tremblay announced measures to tighten the management of government contracts to prevent collusion among tenders.

Quebec's director general of elections said, in a separate news conference, that he's going to convene a group of a dozen ordinary citizens to weigh in on potential reforms to political party financing.

Marcel Blanchet said he wanted people who had no vested interest in political parties to propose solutions to alleged fundraising irregularities.