Police say a third victim was found dead following a separate attack that officers believe could be connected.
Capt. Harry Wadup of the Richelieu-St-Laurent police force says the director general of the Quebec city of Vercheres and his assistant suffered serious stab wounds.
Wadup says the victims were taken to hospital and their injuries are not believed to be life-threatening.
During the subsequent investigation, officers found the body of a man in his 80s outside his Vercheres home.
Wadup says that victim was the suspect's neighbour.
Police say they have arrested a man in his 60s.
They say by the time officers arrived the man had already been subdued by people at Vercheres city hall.