A masked knife-wielding robber who struck Monday in what police believe is the 11th such heist is “priority #1,” Nassau police said Tuesday.

Monday’s robbery had a new twist, with the suspect hitting up the Subway store in New Hyde Park at 1201 Jericho Turnpike at 9:48 a.m., said Det. Lt. Richard LeBrun. All the previous robberies in the pattern occurred at night: between 9 p.m. and after midnight.

“He’s priority #1,” said LeBrun, as police released an image Tuesday of the robber captured on surveillance video before he committed the most recent heist. “Anybody holding a 6 to 7 inch knife is a dangerous individual, especially when they hold it up and point it at you and they say, ‘Open the register.’”

No one has been injured in any of the robberies, LeBrun said.

“He looks into the business; He makes sure there are few employees as possible,” said LeBrun. “He looks around and waits for the perfect time to go in.”

The pattern of robberies since March 1 includes six Dunkin’ Donuts, two Subways, one 7-11 convenience store and two Carvel ice cream shops in a 16-mile area, police said.

advertisement | advertise on newsday

In Monday’s robbery, he walked in with the knife and demanded money from a 20-year-old woman working the counter, police said. He fled with the cash toward North 12th Street, police said.

A police helicopter, equipped with cameras that can zoom in to targets on the ground, was dispatched to the scene, police said.

Crime Stoppers is offering $10,000 for information leading to an arrest.

The robber, about 6 feet tall with a medium build, wears dark-colored clothing, usually a hooded jacket, and hides his face by wearing sunglasses or a bandanna.

Anyone with more information can call Crime Stoppers at 800-244-8477. All information will be kept confidential.

— With Gary Dymski