Jury nullification is the term for when a jury declines to convict a defendant despite overwhelming evidence of guilt. This can be a form of civil disobedience, a political statement against a specific law, or a show of empathy and support to the defendant.
“It’s not a legal defense sanctioned under the law,” said Cheryl Bader, associate professor of law at Fordham School of Law. “It’s a reaction by the jury to a legal result that they feel would be so unjust or morally wrong that they refuse to impose it, despite what the law says.”
This is New York State specific. When the verdict is announced the jury foreperson announces it in open court after it is shown to the presiding judge. At that point the defense Alan request to poll the individual jurors. Occasionally, there is a discrepancy.
Jury deliberations are secret prior to the verdict being announced. Once announced jurors are free to say whatever they want but cannot be compelled.