NEW YORK – Lincoln Rocha had just taken some photographs of his wife while they visited crowded Times Square on a hot summer day when he saw a man nearby start to back away from police officers who were talking to him.

When they reached out to try to grab hold of the man, Rocha said, “He just went for his knife.” The officers went for their guns, and Rocha went for his camera.

“When I saw the officers draw their guns, I was sure they would kill him,” the Brazilian tourist said Sunday, the day after the man, 51-year-old Darrius Kennedy, was shot to death by police, who said he had lunged at officers with the 11-inch kitchen knife.

Kennedy was smoking marijuana near the military recruiting station in Times Square about 3 p.m. Saturday when officers approached, police said. It was the beginning of an encounter that would stretch for seven of the most crowded blocks in New York City in midafternoon and end a few minutes later with 12 gunshots and many witnesses.

As officers spoke to Kennedy, he became agitated and pulled out the knife, police said. He ignored repeated orders to drop the knife and began backing away from them, continuing for blocks as he waved the knife and drew many officers into a slow-speed pursuit that itself lured onlookers.

Officers pepper-sprayed Kennedy six times but he held onto the knife, police said, wiping the spray off his face. Finally, he lunged at police and two officers shot him in the torso, police said. He was pronounced dead at Bellevue Hospital.