Kevin M. O'Shea, the recently demoted chief executive officer of Philadelphia Academy Charter School in the Northeast, has resigned, his lawyer announced this afternoon.

O'Shea submitted his resignation effective at the close of business on Wednesday, said Ronald H. Levine, his attorney.

The departure comes as two separate probes into possible financial mismanagement are winding down at the school which has been shaken during the past month by allegations of financial improprieties, nepotism and conflicts of interest.

The Philadelphia School District's inspector general has spent a month investigating those allegations which emerged when parents raised questions as the district was reviewing whether to allow the school to continue operating for another five years.

In addition, lawyers hired by the charter school board have been conducting their own inquiry.

Two weeks ago, the Philadelphia School Reform Commission decided to delay a vote on renewing the charter to give the inspector general time to investigate.

"Mr. O'Shea is very proud of the achievements of the charter school and of his contributions both as a parent-volunteer, his appointment to the board, and as director of operations and as board-appointed chief executive officer," Levine said. "He very much hopes the school district will renew the charter."

Levine, a former chief of the criminal division in the U.S. Attorney's office, heads the national white collar defense practice at Post & Schell in Center City. He said he has been retained personally by O'Shea to represent him.

Levine said he had informed the charter board's attorneys at Ballard Spahr Andrews & Ingersoll that O'Shea had resigned.

Founded by Brien N. Gardiner in 1999, Philadelphia Academy Charter School has been among the district's most successful charter schools. It enrolls 1,200 children from kindergarten through twelfth grade. Its elementary school is located at 11000 Roosevelt Blvd.; the high school is at 1700 Tomlinson Rd.

O'Shea's resignation comes after several tumultous weeks at the school. As the Inquirer reported last month, district investigators are examining nepotism and a web of charter and business entities that enabled Gardiner and O'Shea to earn more than most school superintendents in the region.

Gardiner, a former district principal, quietly retired from the charter in the summer of 2006 and remained as a paid consultant. O'Shea, a former city police officer with a high school diploma, was promoted from the post of chief operating officer to chief executive officer. He drew a salary of $206,137 as CEO during the 2006-07 academic year, charter salary records show.

Last month, the board first demoted O'Shea and then later placed him and Gardiner on leave with pay.

Larry Sperling, the school's top academic leader, was named acting CEO.