Murder list of murders in Canada with dates
Canada murderers list | Murderpedia
I don't want to teach people to suck eggs but some ideas.

A few things to check if person could be a suspect in a further murder could be as follows:-
Modus Operandi
Date of assault
Could the killer have been in a certain location at a certain time.
Any DNA evidence such as skin cells, sweat, shoe prints.
Does the victim look like any other previous victims.
Are there any available e-fits of the suspect or some CCTV footage even.
Age/Occupation of both the victim and the suspect
Method of transport (For example was a body moved a distance after the murder)
Were previous victims targeted male/female or a mixture of both.
Does the killer always act alone or perhaps with an accomplice.