united-states
In the United States, there are basically only two circumstances where a juror's comments can impeach a verdict, allowing the jury verdict to be set aside and opening the door to a new trial.
- The juror's statement reveals outside influence or corruption or an clerical mistake in filling out the jury verdict forms (e.g., "I was bribed to rule this way", or "There was a man with a gun in a dark corner of the jury room saying he would shoot us if we didn't vote the right way", or "we did an Internet search on our phones and found out that key excluded evidence showed he was guilty."). See, e.g., Federal Rule of Evidence 606 (which has a close parallel in all state law rules of evidence, sometimes with different numbering), which says:
Rule 606. Juror’s Competency as a Witness
(a) AT THE TRIAL. A juror may not testify as a witness before the
other jurors at the trial. If a juror is called to testify, the court
must give a party an opportunity to object outside the jury’s
presence.
(b) DURING AN INQUIRY INTO THE VALIDITY OF A VERDICT OR INDICTMENT.
(1) Prohibited Testimony or Other Evidence. During an inquiry into the
validity of a verdict or indictment, a juror may not testify about any
statement made or incident that occurred during the jury’s
deliberations; the effect of anything on that juror’s or another
juror’s vote; or any juror’s mental processes concerning the verdict
or indictment. The court may not receive a juror’s affidavit or
evidence of a juror’s statement on these matters.
(2) Exceptions. A juror may testify about whether: (A) extraneous
prejudicial information was improperly brought to the jury’s
attention; (B) an outside influence was improperly brought to bear on
any juror; or (C) a mistake was made in entering the verdict on the
verdict form.
- The juror's statement reveals jury deliberations showing that the verdict was based upon racial or ethnic prejudices or stereotypes. See Peña-Rodriguez v. Colorado, 137 S. Ct. 855 (U.S. 2017). This case effectively holds that Federal Rule of Evidence 606(b)(1), and parallel state rules of evidence, are partially unconstitutional.
None of the allegations in the question could be considered by a court, nor could they be used to set aside the jury verdict.
Note also that a jury verdict acquitting a defendant cannot be set aside based upon evidence from a juror that the jury believed that the defendant was guilty but declined to convict because the crime was unjust, or because the circumstances showed some motive for the crime that is not a legally justified defense to the charges. When this happens, it is called "jury nullification" and the rules of evidence are designed to protect that possibility.
In criminal cases, acquittals cannot be appealed or reconsidered, except for the grounds set forth in Federal Rule of Evidence 606(b)(2)(B) and (C), due to the constitutional prohibition on placing a person in "double jeopardy."
In general, the case law holds that Federal Rule of Evidence 606(b)(2)(C), and parallel state rules of evidence, permitting juror testimony concerning clerical errors in filling out the jury verdict forms, can only be raised in the very short time period between when the jury delivers its verdict forms to the judge and the time period after the jury has been discharged but before the jurors have dispersed in a manner that prevents them from being immediately reconvened to testify regarding the clerical error question. This window of time is usually less than an hour after the jury verdict forms are submitted.
Also, unlike Australia, jurors in most U.S. jurisdictions are free to discuss their deliberations with the public at any time after they are discharged, although they are not required to do so. Indeed, in jury trials in Colorado, jurors and the lawyers for both sides are often encouraged by the judge to discuss the jury's deliberations immediately after the jury is discharged. In part, this is done to allow any clerical errors in filling out the jury verdict forms to be discovered and corrected before it is too late to do so.
