When Warner Katz was an Army scout in a dense jungle behind enemy lines during World War II, his exploits and valor were the stuff of which movies are made. As a "lead scout" with the legendary Merrill's Marauders, "Warner would be the first to encounter the enemy and very likely the first to be shot," according to Robert E. Passanisi of Lindenhurst, N.Y., historian for the Merrill's Marauders Association. While scouting on a jungle trail in Burma one day, Mr. Warner spotted a Japanese soldier, smiling and waving his arms. Warner recognized a trap and fired while 20 or 30 soldiers emerged and began firing at him.

"One machine gun bullet caught the left lip of Warner's nose and grazed his cheek. Warner's single round killed the enemy soldier thereby making him the first American infantryman to kill an enemy in the China, Burma, India Theater of War," according to an e-mail from Passanisi. "Warner was also the first Marauder to be wounded." On Aug. 19, 1944, The New York Times subheadlined its story about his survival in Burma, "Sergeant Katz First American to Kill Japanese There." Mr. Katz was credited with saving "innumerable additional casualities" when he was inducted into the prestigious Army's Ranger Hall of Fame in 2000.

Mr. Katz, who in 1944 was mistakenly reported to have been killed by enemy fire the same day he killed the Japanese soldier, died Nov. 5 at Brigham and Women's Hospital of complications of congestive heart failure. He was 87 and lived in Newton. Mr. Katz lived the American dream of many immigrants. He fled Nazi Germany and joined his brother, who was living in Italy, eventually arriving in New York at age 18, penniless and with no knowledge of English. But he worked hard and eventually became a wholesale fur merchant.

When Mr. Katz volunteered for the elite Army combat unit, Merrill's Marauders, knowing how dangerous it was, he did so out of gratitude to the country that had given him haven, said his son, Douglas I. of Newton. "In his civilian life, Dad was not adventurous," he said. "He looked at the things he had done during the war as his duty and a way of helping to bring the war to an end. It was his way of returning that gift. He didn't think of himself as particularly brave. He was just doing his part." Before his service with the Marauders, Mr. Katz served in combat with the American Division in the Solomon Islands. Mr. Katz's awards include the Bronze Star, Purple Heart, and the Presidential Unit Citation.

When he was inducted into the Ranger Hall of Fame, his citation said that "a number of times in various situations he left his safe position within the perimeter to drag wounded comrades to safety. He was the first Marauder to kill an enemy and also the first to be wounded but he refused to be evacuated." Passanisi called him "a special kind of person, for he didn't know what or where he would be going, only that he was needed." But Mr. Katz, he said, was also "a good friend and my buddy." While in Burma, Passanisi said, Mr. Katz endured numerous illnesses, as well as exhaustion.

He was evacuated to India for treatment of malaria and typhus, his son said, after serving with the Marauders from January 1943 until it was deactivated in August 1944. "He went through all of the hell that a soldier can possibly experience," said Passanisi. Mr. Katz was born in Bad Wildungen, a small town near Frankfurt, to Isaac and Johanna (Leopold) Katz. His father was a horse dealer and later a car dealer. "I had a very loving family and we were well off," he told his granddaughter, Rachel of Newton, in an oral history he made for her class at Bates College. "We were happy and lived peacefully until Hitler came. I felt like a German until Hitler came."

He was 13 when Adolf Hitler rose to power. "In school, my friends began to look at me as an enemy," he told his granddaughter. "They hated me because I was a Jew." When it was time for him to leave, "he was one of the lucky Jews chosen to enter the kibbutz in Palestine," his granddaughter said. But he was unable to get a visa, so at 15, with help from a Russian friend of his brother, he slipped across the border into Switzerland and joined his brother, Julius, in Italy. Mr. Katz began his career in the fur business with his brother in Italy. But when life became dangerous for Jews there under the facist leader Benito Mussolini, he decided to go to the United States. An influential friend of an uncle who was already in the United States helped him get a visa, his granddaughter said, and he arrived in New York in 1938.

"When Warner arrived in America, he felt like he was in Italy again," she said. "He didn't know the language very well and couldn't get a job." But he loved the freedom. He lived with another uncle while going to night school to learn English. He took jobs as a busboy, a doorman, and an usher in a movie theater. In the oral history, Mr. Katz told how after his arrival in the United States, his mother was sent to a concentration camp in Lithuania, where she died along with her three sisters and other family members. "Most of my family died there," he said. His father died of "medical complications" in a Jewish hospital in Frankfurt. His brother, Julius, also left Europe and came to the United States.

In 1941, though still not an American citizen, Mr. Katz was drafted into the Army and sent to the Pacific theater. He was promoted to corporal and then sergeant. After he returned from the war, Mr. Katz was assigned to interview German prisoners of war in Virginia for the Office of Strategic Services, the forerunner of the CIA. In 1950, he married Carol J. (Kamborian). She died two years ago  Mr. Katz retired from the fur business in New York when he was in his 60s and he and his wife moved to Massachusetts in 1992 to be near their family. Here he spent quality time with his grandchildren, said his grandson Daniel of Newton.

"It was the little things my grandfather did which made him the unforgettable and amazing man we all knew him as," he said in his eulogy. "He taught me not to forget how lucky I was, to always work my hardest no matter what, and to stretch my mind, my muscles, and my heart."