The Charbonneau Commission inquiry renewed its focus on the Quebec Federation of Labour, its powerful pension fund and the influence wielded on it by people tied to organized crime.
The province's largest labour group was under the microscope for much of the fall sitting of the inquiry over accusations its 70,000-member construction wing was under Mob control.
The inquiry focused on cosy relationships between figures affiliated with organized crime and Jocelyn Dupuis, a former union boss with the federation's construction wing.
The heavy scrutiny prompted the federation's longtime boss, Michel Arsenault, to quit. The new leadership assured just last week the 600,000-member federation would be vigilant against corruption this year.
Since it began sitting, the inquiry has focused on corruption in the construction industry, illegal party financing and the ties between unions and organized crime.
An interim report for the Quebec government is due by Jan. 31.
That was one of the requirements made by the province when it extended the mandate of the inquiry last year.
The final report is due in April 2015.