Threat and Intimidation after joke misunderstanding - How it will play out

Employee A wrote a joke in another language saying "I am rude" on Employee B's workstation.

Employee B later found out and got angry. Employee A explained that it was only meant as a joke and apologized, but Employee B doesnt accept the apology and warned Employee A that he will regret what he (employee A) has done and will make his office life miserable.

Employee B started saying loud negative remarks against Employee's A including race in general.

And with the assistance of the supervisor, Employee B also resorted to publicizing  Employee A's faults whenever found in his work for 2 days.  The supervisor also removed Employee A from the group's media circle.

Employee A tried to reconcile with Employee B again but B vehemently reacted ( in text) how he is against the likes of Employees A's race in the office and warned Employee A  to be careful of not making mistakes at work.

Due to fear,  Employee A's production started to suffer and reported the threat and intimidations made by Employee B to HR.

Base on legalities, what are usually HRs sanction for such actions like employee B and the supervisor ?

Will Employee A be also held liable as the cause of the intimidation began with the joke ?

Depending on your policy. And if anything can be proven.

Top of mind,

for employee A - malicious mischief
For Employee B and the Supervisor - though hard to prove, would be harassment (not the kind of harassment with sexual in nature).

Thanks.

Employee A - even if it was meant as a joke only ? And is it enough grounds for termination ?

Employee B + supervisor - the threat was in digital text. Other witness testimonial is also in digital text. Is that not proof and enough grounds for termination ?

A lot depends on the culture and the policies of the company. the gravity of this incident is hard to gauge but if racism is involved it can be serious.