I was listening to NPR a couple years ago and someone was mentioned who taught the Japanese soldiers that Buddhism said it's ok to kill sick animals, and to treat the Chinese the same way, then after that debacle, he ended up in the US teaching Zen Buddhism to beatniks? I don't remember anything other than that, and I haven't found anything via google. :(
Could it be Hakuun Yasutani, perhaps? He taught Zen in the 60s in the US and his books and his lectures on zazen were some of the first ever translated to English. He also said this little jewel right here in the year 1943.
Of course one should kill, killing as many as possible. One should, fighting hard, kill every one in the enemy army. The reason for this is that in order to carry [Buddhist] compassion and filial obedience through to perfection it is necessary to assist good and punish evil. . . . Failing to kill an evil man who ought to be killed, or destroying an enemy army that ought to be destroyed, would be to betray compassion and filial obedience, to break the precept forbidding the taking of life. This is a special characteristic of the Mahāyāna precepts.
Source: "Zen as a Cult of Death in the Wartime Writings of D.T. Suzuki" in The Asia-Pacific Journal, Vol. 11, Issue 30 , No . 4 , August 5, 2013