Polish historian Jan Grabowski, a son of Holocaust survivors teaching in the University of Ottowa,Canada, has published a number of books and articles claiming that Poles also took part in a pogrom against Jews during World War II.
The Polish Anti-Defamation League has initiated a campaign against him for defaming Poland and blackening its name and is demanding that he be tried in court.
In the wake of the protest, Grabowski has suffered threats to his life and Ottowa police have placed patrols near his house.