He's been caught on surveillance video using counterfeit $100 bills at a gas station in Calverton and at restaurants in Riverhead and Wading River.
Now Suffolk County police are asking the public's help identifying and locating the man.
The suspect has passed the counterfeit currency four times at four different locations since Oct. 1, police said. Each time he purchased "low-dollar amount" items and received cash back, according to police.
Police are asking anyone with information to call Crime Stoppers at 800-220-TIPS. All calls will remain confidential and callers are eligible to a cash reward of up to $5,000 for information leading to an arrest.