In a murder case, 12 people are selected to form the jury after the Crown counsel (representing the Queen or the State) and defence lawyer (representing the accused) have had an opportunity to observe them and ask questions. The members of the jury are selected because of their lack of prejudice and lack of prior knowledge about the case. This jury will determine if the accused is guilty or not guilty, based on the evidence they hear presented during the trial. They are called the “triers of fact.” 

Mennonite Central Committee Canada. (2011). Getting through the maze: A guidebook for survivors of homicide.