Suffolk police are searching for a masked gunman they believe robbed 14 businesses in several towns, including six Subway restaurants, since early December.

Armed with a handgun, the serial robber usually hits businesses between 7 p.m. and midnight, but his most recent robbery was 12:25 a.m. Tuesday at the Mobil gas station on Sunrise Highway in Islip Terrace, police said. He steals cash, then runs away, police said.

He appears to have first struck Dec. 9 at the Medford Subway on Route 112, then struck there again Dec. 11, police said.

The robber appears to be between 5 feet, 6 inches tall and 5 feet, 10 inches, police said. In addition to a mask, he wears a hooded sweatshirt and dark-colored scarf, police said.

Along with the Mobil and Medford Subway robberies, the suspect is also responsible also for the following 11 robberies, according to detectives in the pattern crime unit:

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

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

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

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

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

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

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.