Canadian Criminal Procedure and Practice/Trials/Juries
Jurors bring their own life experience's to their task.
A prospective juror is presumed capable of "setting aside their views and prejudices and acting impartially between the prosecution and the accused upon proper instruction by the trial judge on their duties."
Members of the jury are to come to a unanimous conclusion on the verdict. They do not have to agree on the means or path to that verdict.
Discharging a Juror
Section 644 (1) and (2) states that:
(1) Where in the course of a trial the judge is satisfied that a juror should not, by reason of illness or other reasonable cause, continue to act, the judge may discharge the juror.
Trial may continue
(2) Where in the course of a trial a member of the jury dies or is discharged pursuant to subsection (1), the jury shall, unless the judge otherwise directs and if the number of jurors is not reduced below ten, be deemed to remain properly constituted for all purposes of the trial and the trial shall proceed and a verdict may be given accordingly.
A juror can be discharged where there is well-established information that a juror's impartiality is in questioned.
The judge will make inquiries to the alleged biased juror in open court. Counsel will be able to make submissions and suggest questions to be put to the juror.
A judge has the discretion to discharge a juror under s. 644 and continue the trial or can dismiss the jury and declare a mistrial.  The procedure requires the judge to:
- "apply the proper legal test for determining whether the information gives rise to a reasonable apprehension of bias”, and
- "at a minimum, conduct an inquiry into the circumstances in order to obtain the necessary information upon which to exercise his or her discretion" 
Jurors can be dismissed during deliberations.
The jury can be reduced to as little as 10 members without a mistrial or a violation of s. 11(f) Charter rights.
It exists today in section 649:
Disclosure of jury proceedings
649. Every member of a jury, and every person providing technical, personal, interpretative or other support services to a juror with a physical disability, who, except for the purposes of
- (a) an investigation of an alleged offence under subsection 139(2) in relation to a juror, or
- (b) giving evidence in criminal proceedings in relation to such an offence,
discloses any information relating to the proceedings of the jury when it was absent from the courtroom that was not subsequently disclosed in open court is guilty of an offence punishable on summary conviction.
R.S., 1985, c. C-46, s. 649; 1998, c. 9, s. 7.
This rule, however, does not prevent the court from taking evidence from a third party or a juror about problems that may taint the verdict.
Once the jury gives a verdict the judge is functus and so cannot deal with any issues of irregularities in deliberation.
- R. v. Budai, 2001 BCCA 349 at 27-40
R. v. Wolfe, 2005 BCCA 307 at para. 5 (“When a juror’s conduct raises questions of possible bias, the trial judge may discharge the juror or dismiss the jury and declare a mistrial. Whether to take such a step is a matter which falls within the discretion of the trial judge....”)
- R. v. Chambers 1990 CanLII 47 (SCC),  2 S.C.R.1293
- Budai at 39
- Budai at para. 40
- R. v. Krieger,  A.J. No. 683 (C.A.)
R. v. Peters, 1999 BCCA 406, 137 C.C.C. (3d) 26 (B.C.C.A.)
R. v. Kum, 2012 ONSC 1194
- R .v. Genest 1990 CanLII 3175 (QC CA), (1990), 61 C.C.C. (3d) 251(Que.C.A.)
- dating back to "Lord Mansfield's Rule" of 1785 which prohibits evidence of jury deliberation
- R. v. Pan, 2001 SCC 42
- see R. v. Lewis, 2012 ONSC 1074 (S.C.J.) and R. v. Mirza,  1 A.C. 1118
Determined facts after a jury trial
724. (1) In determining a sentence, a court may accept as proved any information disclosed at the trial or at the sentencing proceedings and any facts agreed on by the prosecutor and the offender.
(2) Where the court is composed of a judge and jury, the court
- (a) shall accept as proven all facts, express or implied, that are essential to the jury’s verdict of guilty; and
- (b) may find any other relevant fact that was disclosed by evidence at the trial to be proven, or hear evidence presented by either party with respect to that fact.
(3) Where there is a dispute with respect to any fact that is relevant to the determination of a sentence,
- (a) the court shall request that evidence be adduced as to the existence of the fact unless the court is satisfied that sufficient evidence was adduced at the trial;
R.S., 1985, c. C-46, s. 724; 1995, c. 22, s. 6.
The primary principles the court must follow to determine facts subsequent to a jury trial:
- The sentencing judge must determine the facts necessary for sentencing from the issues before the jury and from the jury's verdict.
- The sentencing judge is bound by the express and implied factual implications of the jury's verdict, and must accept as proven all facts express or implied that are essential to the jury's verdict.
- The sentencing judge must not accept as fact any evidence consistent only with a verdict rejected by the jury.
- When the factual implications of the jury's verdict are ambiguous, the sentencing judge should not attempt to follow the logical processes of the jury, but should come to his or her own independent determination of the relevant facts.
- Aggravating facts must be established beyond a reasonable doubt. Other facts must be established on a balance of probabilities.
- The sentencing judge should therefore find only those facts necessary to permit the proper sentence to be imposed in the case at hand. The judge should first ask what the issues on sentencing are, and then find such facts as are necessary to deal with those issues.
- Based on R. v. Brisson, 2009 BCSC 1606 (CanLII), 2009 BCSC 1606 at para. 5, summarizing the principles in R. v. Ferguson, 2008 SCC 6 (CanLII),  1 S.C.R. 96 at paras. 17-18
Guilty plea in a Jury trial
A guilty plea before the commencement of a jury trial is to be accepted by the presiding judge. A change of plea during a jury trial should be done to the judge presiding. This is despite the fact that the accused was put in charge of the jury.
The accused does not need to re-elect to another mode of trial to put in the guilty plea. By contrast, the older method would involve the jury taking the plea directly from the accused, if the guilty plea were to occur during the trial.
- R v Luis (1989) 20 CCC (3d) 298 (Ont HCJ)
- eg. R v Rowbothham,  2 SCR 463 at 36 - judge accepts a “directed verdict” of not guilty
see also Ewaschuk, Criminal Pleadings and Practice in Canada at 14:1080
- R v Murray 2000 NBCA 2
- See R v Walker,  SCR 214