Long Island’s serial knifepoint robber struck twice Tuesday, first at a Suffolk grocery store and then at a Nassau electronics and game store, authorities said.

In his 11th strike in two months, the suspect brandished a knife at The Barn on Belmont Avenue in West Babylon and ran off with cash shortly after 1:45 p.m., Suffolk police said. No one was injured.

“Somebody came in with a hoodie, pulled a knife out and said, ‘Give me your money,’ ” said Donna Dawes, night manager at The Barn. Dawes spoke to the employee who faced the robber.

Then just before 9 p.m. in Merrick, he hit for a 12th time: The robber was armed with a large kitchen knife when he held up a GameStop on Sunrise Highway, then fled east toward Henry Street with money from the cash register, Nassau police said. No injuries were reported.

The suspect wore a black hooded jacket, jeans, gray gloves, a black knit cap and a dark mask, Nassau police said.

Detectives said the description matched the suspect who has been wanted since mid-February. Investigators from Suffolk’s major case section and Nassau’s robbery squad have since combined forces to try to catch the suspect.

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Counting Tuesday’s holdups, investigators said they believe the suspect has held up four businesses in Suffolk and seven in Nassau.

The spree includes an attempted robbery, authorities said. He brandished a machete at a Dunkin’ Donuts in Seaford on Feb. 15, but ran off when an employee told him there was no money in the cash register, police said.

Police said the suspect wears a mask or covers his face. He used a machete in the first several crimes, then switched to a knife, police said. He appears to be stocky, about 5-foot-8, they said.

Despite the latest holdup, Dawes, who has been robbed before, said she’s not worried.

“They just want their money and they’re gone,” she said.

Detectives ask anyone with information to call Crime Stoppers at 800-244-8477 in Nassau or 800-220-8477 in Suffolk.

Police said the other crimes fitting the pattern are:

  • Feb. 13: Carvel, 1075 Montauk Hwy., Copiague
  • Feb. 15: Dunkin’ Donuts (attempted), 4007 Merrick Blvd., Seaford
  • Feb. 15: Carvel, 319 Northwest Dr., South Farmingdale
  • March 20: Subway, 1195 Sunrise Hwy., Copiague
  • March 21: Carvel, 4246 Hicksville Rd., Bethpage
  • March 26: Carvel, 810 Carman Ave., Westbury
  • March 28: Subway, 347 Old Country Rd., Carle Place
  • April 1: Carvel, 290 Ronkonkoma Ave., Lake Ronkonkoma
  • April 4: Subway, 1022 Old Country Rd., Plainview
  • April 8: Subway, 890 Old Country Rd., Westbury

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With Joan Gralla