An armed serial robber being sought by police struck twice Tuesday night in Suffolk, holding up a Lake Ronkonkoma convenience store before targeting a Shirley fast food place, Suffolk police said Wednesday.

A grainy image of the suspect, accused of 14 other commercial robberies, was captured on videotape near the Best Express at 336 Ronkonkoma Ave., which was held up about 7:45 p.m. Tuesday, police said.

The robber then hit Kentucky Fried Chicken on Montauk Highway in Shirley at 10 p.m., police said.

Armed with a gun, the suspect has been targeting businesses since Dec. 9, police said, and almost all the holdups have occurred between 7 p.m. and midnight.

He seems to target cash-type businesses, said Det. Lt. Edward Reilly of the pattern crime unit.

He wears a ski mask or uses a dark scarf to hide his face, the detective said, adding holds up a gun or points it from his waistband, saying "Give me the money."

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In each crime, the suspect has gotten away with at least a few hundred dollars, but in the Christmas Day robbery of Sunoco in Coram, he made off with about $2,000, Reilly said.

In some cases, the victims see him running off, police said.

"We don't know if he has a car off the site," Reilly said.

He hasn't injured anyone in the robberies, the lieutenant said, but anyone who sees him should call police instead of chasing him down: "We just tell people to be cautious. Just because he didn't hurt anybody doesn't mean he's not dangerous. He is dangerous."

The robber appears to be between 5 feet, 6 inches and 5 feet, 10 inches tall, police said.

He is also responsible for the following 14 robberies, according to detectives in the pattern crime unit:

Mobil on the Run, 3239 Sunrise Hwy., Islip Terrace, Jan. 7

Subway, 600-7 Portion Rd., Lake Ronkonkoma, Jan. 5

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Subway, 173 Smithtown Blvd., Nesconset, Jan. 3

7-Eleven, 2810 Rte. 112, Medford, Jan. 3

Royal Market, 451 Glen Drive, Shirley, Jan. 2

Carvel, 536 Main St., Center Moriches, Jan. 1

Hess, 1801 N. Ocean Ave., Medford, Dec. 31

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Subway, 600 Portion Rd., Ronkonkoma, Dec. 29

Subway, 402 Rte. 112, North Patchogue, Dec. 28

Hess Express, 440 Portion Rd., Ronkonkoma, Dec. 26

Sunoco, 3423 Rte. 112, Coram, Dec. 25

Hess, 3203 Rte. 112, Medford, Dec. 15

Subway, 2920 Rte. 112, Medford, Dec. 11

Subway, 2920 Rt. 112, Medford, Dec. 9

Anyone with information may call Crime Stoppers at 800-220-TIPS. To report a crime anonymously, call 800-220-TIPS or text SCPD and your message to CRIMES (274637) or visit tipsubmit.com. You may be eligible for a reward of up to $5,000 if your tip results in an arrest.