Answer based on context:

The Knights, under the leadership of Heinrich von Plotzke, agreed to aid Bogusza, and a force of 100 knights and 200 supporters, led by Günther von Schwarzburg, arrived at the castle around August. While historians agree that the castle as well as the adjacent town were in the hands of the Teutonic Knights by late November 1308 the number of casualties and the extent of destruction is debated. Peter Oliver Loew writes that for a long time German historians accepted the version of events given by Teutonic Knights, and didn't accept a high number of people murdered, with the number given between 60 and 100 victims Błażej Śliwiński, based on several sources argues that the number of murdered was very high, even if not 10,000. According to Peter Oliver Loew the exact numbers can never be established, however he agrees that all available data confirms that the city was destroyed during the conquest.

How many people may have been murdered according to Błażej Śliwiński?
10,000