He was the commanding officer responsible for the execution of men and teenage boys in the Kragujevac massacre, when Serbian civilians were murdered in reprisal for an attack on German troops, at the ratio of one hundred Serbs for every German soldier killed.

Kuntze was assigned Deputy Wehrmacht Commander Southeast and Commander-in-Chief of the 12th Army on 29 October.

It is preferable that 50 suspects are liquidated than one German soldier lose his life…If it is not possible to produce the people who have participated in any way in the insurrection or to seize them, reprisal measures of a general kind may be deemed advisable, for instance, the shooting to death of all male inhabitants from the nearest villages, according to a definite ratio (for instance, one German dead: 100 Serbs, one German wounded: 50 Serbs).

"Kuntze surrendered to the Allied troops in 1945 and was tried at the Hostages Trial in 1947.

He was found guilty and sentenced to life imprisonment, but was released on medical parole in 1953.