The knife-wielding repeat robber wanted in Suffolk and Nassau by federal and local authorities has a new total: The bandit has hit 17 businesses across Long Island, the latest a Subway sandwich shop in North Lindenhurst on Wednesday, Suffolk County police said.

Suffolk police announced yesterday they had also linked the suspect to another location — a Game Stop store on Veterans Highway in Islandia that was held up at 6 p.m. on May 3 — and said the FBI has joined the investigation.

“We’re dealing with a desperate, dangerous criminal,” said Suffolk Police Commissioner Timothy Sini during a news conference at police headquarters in Yaphank. “His motivation is, of course, unknown to us, but it’s likely money.”

Sini said the Nassau County Police Department, which is investigating 13 of the 17 robberies in the pattern, and the FBI are working in concert to apprehend the bandit.

He said police are increasing patrols in areas where the bandit is likely to hit, based on a profile developed by analysts in the department’s Homeland Security and Criminal Intelligence Bureau.

Sini declined to specify the investigative techniques used. But one example would be putting tiny GPS tracking devices on business establishments’ money packs to track thieves.

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The robber struck again late Wednesday, making it three robberies in two days and 17 across Nassau and Suffolk counties since March 1, police said.

No one has been injured in any of the heists.

The latest robbery, of a Subway store in North Lindenhurst, was the fourth overall in Suffolk, officials said.

The masked man has struck mostly in Nassau — hitting at least seven Dunkin’ Donuts shops, two 7-Elevens, two Subway sandwich shops and two Carvel ice cream stores — between about 9 p.m. and 12:30 a.m., police said.

As in most of the other robberies, a lone employee was in the Subway at 66 Sunrise Hwy. in North Lindenhurst at 9:45 p.m. Wednesday when the robber struck. He threatened the employee with a knife and took the cash drawer from the register, police said.

At one point, the clerk “engaged him to get a certain piece of property back,” Sini said. Police would not specify the property, nor say whether the thief gave it back.

Suffolk police responded with canine and aviation units, but the thief once again proved elusive.

Police said the suspect’s description matched that of previous robberies, where witnesses said he is about 25 years old, 6 feet tall with a medium build. He wears a dark-colored hooded jacket, jeans and tan work boots, and covers his face with dark sunglasses and a dark-colored cloth, police said.

In the earlier robbery on Wednesday, in Nassau, the suspect wore a bandanna and sunglasses when he took an unspecified amount of cash from a 7-Eleven in Westbury at 12:30 a.m., Nassau police said.

At 12:01 a.m. Tuesday, Nassau police believe the same suspect took cash from an Elmont Dunkin’ Donuts.

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Nassau County Det. Lt. Richard LeBrun urged residents to be on the lookout when entering small businesses.

“We are very, very concerned,” he said. “He is becoming more brazen. He needs to be captured and apprehended by the police.”

Anyone with more information can call Crime Stoppers, which has in this case increased its reward offer to $10,000, at 800-244-8477. All calls will be kept confidential.