Robert Rousseau was the director of the borough's division of permits and inspections.
According to Alain Gravel, the host of Radio-Canada's investigative program Enquête, the City of Montreal's comptroller general was also investigating Rousseau in relation to the Upper-Lachine-Wilson condominium project — a controversial construction project belonging to Tony Magi, a known associate of the Montreal Mafia.
Gravel said the comptroller-general is also investigating another former senior borough manager, Jean-Yves Bisson, in connection to that project. A city engineer suspected of taking bribes has also been suspended.
A spokesman for the borough confirmed the death of an employee, but did not identify him by name.
"Our thoughts are with the family and colleagues who have been struck by a terrible shock today," the borough said in a short statement.
City of Montreal Mayor Michael Applebaum, the former borough mayor of Côte-des-Neiges-Notre-Dame-de-Grâce, has refused comment out of respect for Rousseau's family.