Suffolk County police are asking the public’s help identifying the thief seen stealing cellphones in surveillance video from a big-box store in Islandia last month.

Police released video that shows the man step up to the display case, take a cellphone, stick it into his pocket and walk away. Seconds later, the same man, wearing a white Yankees baseball hat, returns — this time stopping at a nearby display where he takes a cellphone and, while nervously keeping an eye on passing shoppers at the BJ’s Wholesale Club store last month, cuts the security cable, slips the phone into his pocket, too — and again walks away.

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Police said the theft occurred about 12:10 p.m. on July 28 at the store on Old Nichols Road. The two phones were valued at about $1,700, police said.

Video of the thefts can be viewed by clicking on the link for Wanted for Grand Larceny CC#17-443497 at YouTube.com/scpdtv, police said.

Anyone with information about the thefts is asked to call Crime Stoppers at 800-220-8477. All calls will remain confidential and callers are eligible for a cash reward of up to $5,000 for information leading to an arrest.