Officer Craig Matthews fired seven times and Officer Robert Sinishtaj fired nine times at Jeffrey Johnson on a busy Friday morning in the highly touristed area after Johnson shot a former co-worker to death and then pointed his pistol at them.
Based on ballistic tests and other evidence, "it appears that all nine of the victims were struck either by fragments or by bullets fired by police," Commissioner Raymond Kelly said Saturday.
Investigators were trying to piece together what caused Johnson to ambush former colleague Steve Ercolino, a vice president at the company where Johnson was laid off last year.
Police said Johnson hid behind a car and killed Ercolino with five gunshots as he arrived for work. Johnson then walked away before being shot by two police officers who confronted him moments later.
Security camera footage showed the officers had only an instant to react when Johnson turned as they approached and pointed his gun at them, his arm cocked as if to fire.
Their encounter was over in eight seconds. The officers, who had been standing nearly close enough to shake hands with Johnson, fired almost immediately.
Nine bystanders were wounded in the 16-shot volley, all by stray or ricocheting police bullets. None of their injuries was life-threatening, police said.
Johnson and Ercolino had traded harassment accusations when they worked together, police said, and when Johnson was laid off a year ago he blamed Ercolino, saying he hadn't aggressively marketed Johnson's new T-shirt line.
A neighbour who often saw Johnson, 58, said he was always alone.
"I always felt bad," said Gisela Casella, who lived a few floors above him. "I said, 'Doesn't he have a girlfriend?' I never saw him with anybody."
Ercolino, 41, was described by his relatives as the opposite of a loner.
His eldest brother, Paul Ercolino, said he was a gregarious salesman who often travelled, had a loving girlfriend and was the life of any family gathering.
"He was in the prime of his life," he said.
The shooting shocked New Yorkers from their morning routines, with people sprawled in the streets bleeding and a tarp covering a body in front of one of the world's most well-known buildings.
The officers who fired were part a detail regularly assigned to patrol landmarks since the Sept. 11 attacks, officials said.
Kelly, the police commissioner, said the officers who confronted Johnson had "a gun right in their face" and "responded quickly, and they responded appropriately."
"These officers, having looked at the tape myself, had absolutely no choice," he said.
A loaded magazine was found in Johnson's briefcase. Johnson legally bought the gun in Florida in 1991, but he didn't have a permit to possess it in New York City, authorities said.
Mayor Michael Bloomberg on Friday said New York still is the safest big city in the country, on pace to have a record low number of murders this year.
"But we are not immune to the national problem of gun violence," he said of the shooting, which followed recent mass shootings at a Colorado movie theatre and a Sikh temple in Wisconsin.