The office of the Manhattan district attorney, Cyrus R. Vance Jr., and the S.E.C. declined to comment.

Image Gov. Chris Christie Credit... Doug Mills/The New York Times

Since the lane closing scandal widened this year, Mr. Christie’s office has been the subject of investigations by the United States attorney in Newark, Paul J. Fishman, and the New Jersey Legislature. Mr. Christie also ordered an internal investigation of his office, an effort that cost millions and which cleared him of any wrongdoing. At a moment when the governor’s stewardship of state finances has faced mounting scrutiny, the Skyway investigations — and potential disclosures — could undermine his carefully cultivated image as a responsible spender as he tries to move beyond the political fallout from the lane closings.

In addition to the Pulaski Skyway, the Manhattan district attorney is also in the early stages of investigating repair projects on the Goethals and Bayonne Bridges, among others. While prosecutors have issued dozens of subpoenas, no formal accusations have been made and the precise targets of the inquiry, whether individuals or agencies, remain unclear.

The lane closings at the George Washington Bridge are still the subject of a federal investigation.

Among those who have received subpoenas from Mr. Vance’s office is Jeffrey Chiesa, a close friend of Mr. Christie’s for more than two decades who has served as New Jersey’s attorney general and as a United States senator. He was the governor’s chief counsel in 2011 when the authority’s lawyers amended the funding resolution with what critics have said was a questionable legal justification. A person familiar with that subpoena said Mr. Chiesa was not a target of the investigation.

One person briefed on the matter said the funds had been used to fill a hole in the New Jersey state budget, noting that the inquiries seek to determine whether the fiscal contortions were creative politics or criminal maneuvers.

The Christie administration said it wanted to pay for the Pulaski Skyway repairs soon after the trans-Hudson tunnel was canceled. At the time, the state had limited money for major transportation projects, and Mr. Christie, a Republican, resisted increasing the gas tax to raise more. The justification for using the tunnel money for the Skyway was first reported by The Record, a North Jersey newspaper.