NEW YORK — A garment salesman was arrested on charges he systematically killed three shopkeepers as they worked alone in their clothing stores after a pharmacy worker recognized him from surveillance footage. Authorities believe the man had been poised to strike again.

Police said Salvatore Perrone, 63, was taken into custody Wednesday in the suspected serial killings that scores of New York City detectives were investigating.

A pharmacy worker recognized him as the balding man shown in surveillance footage leaving the scene of the most recent shooting, Nov. 16, with a duffel bag, police said.

Another shopkeeper came forward and said Perrone had gone into his store and questioned him about whether he worked alone and when he closed, police Commissioner Raymond Kelly said.

“It’s reasonable to assume he was going to keep doing this, and, by arresting him, we saved lives,” Kelly said at a news conference.

Perrone of Staten Island was arrested on charges of murder. He was in custody Wednesday and couldn’t be reached for comment. A message left on his cellphone was not returned, and it was unclear if he had an attorney.

Detectives said they found the duffel bag at his girlfriend’s home. Inside, they said, was a sawed-off rifle used in the killings, along with .22-caliber ammunition, black gloves, women’s clothing, a bloody knife and a bottle of bleach.

Perrone’s fingerprint was lifted from the murder weapon, Kelly said.

Initially, authorities thought the killer might have targeted the Brooklyn shopkeepers, who were from Iran and Egypt, because of their Middle Eastern backgrounds. But on Wednesday Kelly said there was no motive he could speak of.

In the most recent killing, Rahmatollah Vahidipour, an Iranian, was shot three times in the head and chest at his store, the She She Boutique.

After that killing, detectives discovered the same gun was used in the fatal shootings of two other shopkeepers when ballistics matched the .22-caliber gun shell casings on all three. On July 6, Mohamed Gebeli, an Egyptian, was found shot in the back of his shop, Valentino Fashion Inc. On Aug. 6, Isaac Kadare, also Egyptian, was shot in the head in his store, Amazing 99 Cent Deal.