By Cory James

NEW YORK (CBSNewYork) — Police in Manhattan are searching for a suspect in a string of knifepoint robberies.

Police say during the robberies, the suspect corners victims and threatens them with a knife.

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Investigators believe the suspect has pulled off nine robberies in the past week and at least 15 since Oct. 9.

Surveillance video shows the violent thief with a knife in hand, demanding money from a terrified cashier at Liberty Smoke Shop in Hell’s Kitchen.

Monir Kem told CBS2’s Cory James he handed over $580, but that wasn’t enough.

“Then he hit me here,” Kem said. “‘More money, more money,’ and I don’t have any more money.”

In the surveillance video, the suspect can be heard telling Kem, “If you call police, I’m going to come back here.”

Investigators say the suspect targets people on the street and in restaurants and stores.

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“And in some instances, he displays the knife and uses physical force or places the knife to our victim’s neck,” an investigator said. “So we want to grab him off the street before it does escalate into something tragic.”

Nasir Warich, the owner of Liberty Smoke Shop, says in three years of being open, this was a first.

“Too much crime this area, so everywhere has a big problem right now,” he said.

According to the NYPD, robberies in October 2021 compared to October 2020 increased more than 16% in New York City.

“We just need more security, more vigilance in the neighborhoods … More cops around the neighborhood,” one woman said.

Investigators say the suspect’s gotten away with about $3,400 in cash and stolen credit cards.

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Anyone who has information regarding these incidents is asked to call the NYPD’s Crime Stoppers Hotline at 1-800-577-8477 or for Spanish, 1-888-577-4782. Tips can also be sent to the NYPDTips Twitter account or submitted online at NYPDCrimeStoppers.com.

Cory James