New York ? Eddie Adams, a photojournalist whose half-century of arresting work was defined by a single frame — a Pulitzer Prize-winning Associated Press photo of a communist guerrilla being executed in a Saigon street during the Vietnam War — died Sunday. He was 71.

Adams died at his Manhattan home from complications of amyotrophic lateral sclerosis, or Lou Gehrig’s disease, said his assistant, Jessica Stuart. Diagnosed last May, he quickly lost his speech but remained alert and worked into his final days.

In addition to his photographs of 13 wars, Adams’ images of politics, fashion and show business appeared on countless magazine covers and in newspapers around the world. His portraits of presidents ranged from Richard Nixon to President Bush, and those of world figures included Pope John Paul II, Deng Xiaoping, Anwar Sadat, Fidel Castro and Mikhail Gorbachev.

But fame — instant, enduring and discomforting — resulted from a single photo taken Feb. 1, 1968, the second day of the communists’ Tet Offensive, in the embattled streets of Cholon, Saigon’s Chinese quarter.

Drawn by gunfire, Adams and an NBC film crew watched South Vietnamese soldiers bring a handcuffed Viet Cong captive to a street corner, where they assumed he would be interrogated. Instead, South Vietnam’s police chief, Lt. Col. Nguyen Ngoc Loan, strode up, wordlessly drew a pistol and shot the man in the head.

Adams caught the instant of death in a photo that made front pages around the world. It would became one of the Vietnam’s War’s most indelible images, shocking the American public and used by critics to dispute official claims that the war was being won.

In later years, Adams found himself so haunted by the picture that he would not display it at his studio. He also felt it unfairly maligned Loan, who lived in Virginia after the war and died in 1998.

“The guy was a hero,” Adams said, recalling Loan’s explanation that the man he executed was a Viet Cong captain, responsible for murdering the family of Loan’s closest aide a few hours earlier.

For the photographer, the picture left a daunting legacy: He felt pressure to match the power of the image for the rest of his career, and he faced occasional scoldings from colleagues.

South Vietnamese National Police Chief Brig Gen. Nguyen Ngoc Loan executes a Viet Cong officer with a single pistol shot in the head on Feb. 1, 1968, in Saigon, Vietnam. The photo, by photojournalist Eddie Adams, became one of the Vietnam's War's most indelible images. Adams died Sunday at his Manhattan, N.Y., home.

At an awards ceremony, a Dutch reporter asked, “Why didn’t you stop him from shooting that man?”

Adams couldn’t look at the picture for two years.

“I was getting money for showing one man killing another,” he said soon after he won the 1969 Pulitzer Prize for the photo. “Two lives were destroyed” — the general later encountered immigration difficulties in the United States over the shooting — “and I was getting paid for it. I was a hero.”

Among the more than 500 honors he received in his career, Adams won a 1978 Robert Capa Award and three George Polk Memorial Awards for war coverage.

Born June 12, 1933, in New Kensington, Pa., Adams served as a Marine Corps combat photographer in the Korean War and became one of the nation’s top photojournalists with newspapers, the AP from 1962-72 and again from 1976-80, and with Time-Life, Parade magazine and other publications.

Adams is survived by his wife of 15 years, Alyssa, and a son, August; three children by a previous marriage, Susan Ann Sinclair and Edward Adams II, both of Atlanta, and Amy Marie Adams, of New Jersey; his 100-year-old mother, Adelaide Adams, and four sisters.