Fritz Pfeffer

Friedrich "Fritz" Pfeffer (30 April 1889 – 20 December 1944) was a German dentist and Jewish refugee who hid with Anne Frank during the Nazi Occupation of the Netherlands, and who perished in the Neuengamme concentration camp in Northern Germany.

In Anne Frank's posthumously published diary, all names, apart from those of the Frank family, were changed to preserve the privacy of individuals mentioned. Pfeffer was given the pseudonym Albert Dussel.

source: http://en.wikipedia.org/wiki/Fritz_Pfeffer