During World War II he was imprisoned in a Nazi concentration camp near Radom, from which he escaped in 1944.

The following year he was appointed an interrogation officer in the Gdańsk jail.

From 1946 to 1952 he worked for Haganah Wien in Austria, as Director of Staff of the Documentation Center in Vienna, where he and his colleagues hunted down numerous Nazis.

[3] Afterwards, in Israel, he played a role in the capture of Adolf Eichmann.

The archives at Yad Vashem in Israel contain dossiers on various Nazis, collected by Friedman.