A shopper at a Target store in Copiague used counterfeit $20 bills to buy a vacuum cleaner earlier this month, police said.
The man was seen leaving the store at 1149 Sunrise Hwy. about 12:30 p.m. on Aug. 3 with the Shark vacuum cleaner in a shopping cart, police said.
He drove away in a dark Honda sedan, police said.
Detectives asked that anyone with information on the man call Crime Stoppers at 800-220-8477.
A cash reward of up to $5,000 is available, police said.