The legal problems continue to mount for Yale-New Haven Hospital.

The hospital, which earlier this week settled complaints with the National Labor Relations Board regarding obstruction of union activities, now faces a lawsuit from a former doctor at the hospital, Robert Smith. The suit alleges that the hospital violated the federal False Claims Act, which prohibits hospitals from receiving government payments for false reasons, the New York Times reported Saturday.

The United States attorney is investigating the matter because of the stature of the federal lawsuit, the Times reported. John Hughes, the United States attorney in charge of civil litigation, refused to comment on the status of Smith’s lawsuit.

Smith, who left Yale-New Haven last year for a job at Cornell, said he did not have time to speak to a reporter this week. His lawyer, Mary Alice Leonhardt, did not return several phone calls to her office.

This is the second suit brought against the hospital regarding the False Claims Act. The Times also reported that the Justice Department has filed suit against Yale-New Haven Hospital and over 40 other facilities for similar violations. Other facilities under scrutiny include hospitals in Atlanta, Chicago, Los Angeles and Miami.

Yale-New Haven’s lawyers were unavailable to comment this week, and hospital spokesman Mark D’Antonio said he was unaware of any lawsuit by Smith.

Smith’s suit is the second he has filed against a New Haven institution in the past two years. Last year Smith and longtime Yale radiology professors Morton Burrell and Arthur Rosenfield filed a lawsuit against Yale University alleging improper practices by the radiology department at Yale-New Haven Hospital, the teaching hospital for medical students.

That suit contended that officials in the department ordered doctors with less than four years of experience to examine the X-rays of emergency room patients.