The machete robber has carved out new territory.

Suffolk County police believe the man linked to four holdups and an attempted robbery in Nassau also held up a Copiague sandwich shop last week.

After reviewing video surveillance footage from one of the Nassau robberies, Suffolk detectives determined that the suspect’s clothing, build and weapon of choice — a machete or large kitchen knife — appear to match those in the Copiague holdup.

“We’re investigating it as part of the pattern, just based on the description of the subject,” Suffolk Det. Lt. Shaun Spillane said Wednesday. “And he had a machete.”

The list of targeted businesses, meanwhile, has grown to six, with police adding the Tuesday night robbery of a Carle Place sandwich shop.

No one has been injured in the six-week robbery spree, authorities said. Nassau County CrimeStoppers has offered a $5,000 reward for information leading to an arrest.

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Nassau Det. Lt. Richard LeBrun said both police departments are working “collaboratively” on the case and are dedicating “significant resources to apprehend the offender.”

“The safety and security of the public is always our top priority,” LeBrun said.

In the Carle Place holdup, the robber brandished a large kitchen knife after entering the Subway at 347 Old Country Rd. at 5:53 p.m., police said. He approached a clerk and demanded money from the register.

Gawad Kahn, a manager who was doing inventory at the time, said in an interview that he fumbled opening the safe, entering the wrong code, and the robber yelled: “Come on! Quick, quick!”

The thief dropped some of the money on the floor, but stopped to pick it up. “Have a good day,” he said, before fleeing out the back door, according to Kahn.

The suspect was described as stocky, about 5-foot-8, wearing a dark, waist-length jacket and light-colored cargo pants, police said.

In each of the linked cases, the suspect has concealed his face with a mask or scarf, frustrating investigators.

“His facial outline is obstructed, and at this point we cannot provide a sketch,” LeBrun said.

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Nassau and Suffolk police declined to say whether they’ve used GPS tracking technology in the investigation. Law enforcement agencies have increasingly turned to tiny GPS trackers that can be hidden in money packs to track down thieves.

“We’re taking some investigative steps that we don’t want the public to know about,” Spillane said when asked about the trackers.

Cops, alerted to the suspect’s description, have increased patrols at businesses similar to those targeted, particularly at night when the robber usually strikes.

Police are also deploying plainclothes officers and specialty teams in the hunt for the thief.

The suspect first struck Feb. 15, brandishing a machete at a Dunkin’ Donuts on Merrick Road in Seaford, police said. A worker told him there was no money and he fled without any, police said.

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About a half-hour later, he went to a Carvel ice cream shop on Northwest Drive in South Farmingdale and showed the machete, police said. This time, he made off with a small amount of cash, police said.

He hit the Copiague Subway on Sunrise Highway on March 20, police said. The next day, he robbed a Carvel on Hicksville Road in Bethpage, brandishing a machete, police said.

He robbed a Westbury Carvel on Carman Avenue — this time armed with a large kitchen knife — on Sunday, police said.

With Howard Schnapp