Montreal-based engineering giant SNC-Lavalin said Friday it was co-operating with the RCMP as officers carried out a search warrant at the company's head office on Friday.

The company has faced scrutiny recently over US$56 million in payments for questionable projects.

"The warrant relates to an investigation of certain individuals who are not or are no longer employed by the company," said SNC-Lavalin in a statement Friday.

"As previously stated, the Company is co-operating fully with all investigations regarding this or any other matters, and intends to respond to all requests from the authorities."

The company's former CEO Pierre Duhaime resigned recently in connection with an internal investigation into those payments, which he signed-off on.

The payments went to undisclosed agents for two projects and may have breached the company's code of ethics.

At the time of Duhaime's departure in late March, SNC-Lavalin said the company's CFO and chairman refused to approve the payments in question, but Duhaime stepped in and allowed them to go forward -- a move the company said contravened its code of ethics.

In February, the company's board launched an investigation into $35.5 million in payments, which were previously thought to be linked to its Libyan operations.

That probe was later expanded to include another US$22.5 million worth of payments.

All the payments were attributed to construction projects, but a closer look showed the money never reached those projects.

The company has not specified which projects the issues were related to, but did say it did not believe they were located in Libya.

SNC-Lavalin has been criticized in recent months for maintaining close ties to former Libyan dictator Moammar Gadhafi and his family.

Earlier this year the company fired two employees for having ties to al-Saadi Gadhafi, the son of the now dead dictator who is wanted on an international arrest warrant.

Former executive vice-president Riadh Ben Aissa and Stephane Roy, who was a controller, were "no longer in the employ of the company, effective immediately," according to a release published Feb. 10.

According to reports, Aissa had worked extensively in Libya on projects worth hundreds of millions of dollars.

He also helped al-Saadi Gadhafi set up the Libyan Corps of Engineers and there are reports he flew a Canadian security specialist to Libya to help Gadhafi when tensions were at their highest last year.

Roy has also been linked to an alleged plot to help smuggle Gadhafi into Mexico. Mexican authorities recently charged an Ontario woman, Cynthia Vanier, with masterminding the James Bond-style scheme which involved private planes, forged passports and a safehouse.

Roy was with Vanier at the time of her arrest, SNC-Lavalin later acknowledged, though police did not take action against him.

Vanier's father John McDonald went public this week saying his daughter is innocent and Ottawa hasn't done enough to help her.

Cynthia Vanier was arrested in November and charged in February with attempted human trafficking, falsifying documents and organized crime in connection to the alleged Gadhafi plot.