A relevant scenario:
*A politician has most likely been involved in the murder of a critical citizen because he was seen on a CCTV leaving the murder scene with bloody hands.
*The victims family tries to talk to the politician but he says he won't speak to them.
*The police has chosen not to investigate the crime properly(to protect the politician and his friends);
*The police tells the public no crime has been committed and the citizen must have died because of natural causes;
*The courts are expected to be corrupt and refuse to make logically correct inferences based on the evidence if the victim's family would try to do a private prosecution due to either bribed judges or judges who are afraid of consequences ;
*The media is corrupt and owned by the politician or friends of him and won't help the family.
*The victim's family members use their freedom of speech and start to speak out publicly that they suspect the politician to have been involved the murder of their family member and that the police, courts and media are all corrupt and protects the politician by not performing proper investigations as well as ignoring strong evidence.

The politician brings the victim's family members to court and sues them for defamation. He claims he is innocent based on the police's words that the victim must have died due to natural causes. It has hurt his feelings and reputation to hear that he is accused by the victim's family members, defamation laws exist to protect one's reputation and therefore the court should sentence the family members to pay him a big compensation as well as being thrown in jail for a year(he refers to their accusations as being extreme and has really hurt his feelings and reputation).

How would you help the victims family to argue for the right to freedom of speech on this matters?

Well said, truth is what we find after investigating enough and evaluating enough epistemic defeaters.

If certain hypothesis, bakground data and evidence are not to be discussed, then we can't claim to have found truth.

Thanks to you both for your answers!

Peter will say that you can't know things that you both have not seen. He will also claim that he and the 10 other people can testify under oath in court(risking perjury) that what X has stated is true, because they claim to have seen it, and therefor he is entitled to get the prize money since 11 independent witness testimony under oath should be enough justification and more reliable than your casual reasoning.

Thanks Tim. What I'm aiming for is what probability this would be and if it would be below chance or above chance?