NEW YORK -- The New York attorney general's office has subpoenaed Bank of America ( BAC) seeking the names of Merrill Lynch executives who received $3.6 billion in year-end bonuses, after CEO Ken Lewis failed to provide those details during a lengthy deposition Thursday evening. Lewis, who traveled to New York on the company's corporate jet, said that he "answered the questions that were asked to the best of my knowledge." Lewis's deposition was part of an ongoing investigation by New York Attorney General Andrew Cuomo into the timing of Merrill Lynch's bonuses and whether proper disclosure was made to shareholders about the size of the bonuses. They were granted just before Bank of America's acquisition of Merrill closed, and as that bank was seeking additional government aid on top of $25 billion it had already received. The CEO's use of the company aircraft seemed surprising since it comes at a time when bailed-out banks have faced heavy scrutiny over executives' use of such perks. "Because of the timing of this meeting, we felt it was necessary to use corporate aircraft," said company spokesman Timothy Gilles. Cuomo is "disappointed and frustrated" that Lewis has not cooperated in providing the information, said special assistant Ben Lawsky following the meeting, but he stopped short of saying the discussions had been contentious. Bank of America spokesman Robert Stickler said the bank for the past two weeks has offered to provide the attorney general's office with employees' names if Cuomo would guarantee their confidentiality, but he has declined to do so.