A Levittown man is accused of impersonating a federal worker-safety agent and demanding money from a construction company owner, Nassau police said.

Keith F. Doherty, 42, was arrested Friday in Plainedge. He is charged with two counts of fourth-degree grand larceny for extortion, one count of fourth-degree grand larceny for attempted extortion and three counts of second-degree criminal impersonation, Nassau County police said.

Detectives said Doherty, masquerading as an Occupational Safety and Health Administration employee, went to a Hempstead construction site and demanded an undisclosed amount of cash from the 57-year-old businessman in exchange for overlooking violations.

advertisement | advertise on newsday

Doherty had visited the site three times since Wednesday -- receiving money twice, police said. The victim then contacted authorities.

Doherty is scheduled to appear in First District Court in Hempstead on Saturday.