Beleaguered engineering firm SNC-Lavalin has appointed an outsider as its new chief executive after firing three top executives linked to mysterious payments in North Africa. Robert Card, a former senior executive at CH2M Hill Companies, a Fortune 500 engineering firm with 30,000 staff in more than 80 countries and $6 billion in revenues, will take the reins October 1, the company said in a statement late Friday. He replaces Pierre Duhaime who was sacked in March after 23 years with the company, amid accusations he allowed $56 million in payments to foreign agents for undocumented work. An independent review traced two payments in December 2009 and July 2011 to Riadh Ben Aissa, executive vice-president of the firm's construction arm, who was fired in February along with vice president in charge of finances Stephane Roy. Media reports previously linked Aissa and Roy to the arrest in Mexico of a Canadian woman accused in an elaborate plot to bring 38-year-old Saadi Kadhafi, the son of ex-dictator Moamer Kadhafi, into Mexico with false documents at the height of pro-democracy protests in Libya last year. SNC-Lavalin, which oversaw billions of dollars worth of projects in Libya, including construction of a prison, had hired the alleged conspirator, Cynthia Vanier, for "a fact-finding mission" in Libya in early summer 2011. Mexican authorities charged Vanier, a Dane, and two Mexicans on January 28 with attempted trafficking of undocumented people, organized crime and falsifying official documents. In April, Canadian federal police raided SNC-Lavalin's Montreal headquarters as part of an investigation into the mysterious payments made through its office in Tunisia.