Sharon E. Pandak, the Prince William county attorney, kept a whopper of a secret to herself until last week: her resignation after 25 years with the county, including 15 as county attorney.

"Nobody expected or saw this coming," said Sean T. Connaughton (R-At Large), chairman of the Board of County Supervisors.

Pandak stunned board members and longtime colleagues by announcing her resignation during an executive session of the board of supervisors last Tuesday. It came immediately after her annual performance review, during which she received the county's highest rating and a raise to $174,093 per year. It was also her 51st birthday.

"Sharon has decided she wants to pursue another career and she didn't feel she could do that while still working as the county attorney," county spokeswoman Liz Bahrns said. Pandak has not told her colleagues about any future plans. Her last day will be Aug. 31, although she will continue to be paid for any existing vacation time, Bahrns said.

Pandak's retirement pay will be based on her last three years of employment, so waiting to resign until after she received her latest raise will boost her pension slightly.

Other county government officials surmised that Pandak, who recently got married, simply wanted to make a change after 25 years.

Pandak left on a scheduled family vacation and was not available for comment. But in a lengthy statement and in a two-page resignation letter, Pandak quoted Thurgood Marshall and Alfred, Lord Tennyson and spoke warmly about her colleagues and her years with the county.

"Leaving Prince William County government is not easy for me to do," Pandak wrote in the letter to board members. "Serving as county attorney has been an immense honor and personal challenge.

"With the strengths gained from my past service, I now will pursue other career opportunities," she wrote.

Pandak praised her staff, including her top deputy, Joe Howard, who will serve as acting county attorney until the board names Pandak's replacement.

Pandak was seen as one of the leading municipal attorneys in Virginia and a nationally known expert on land-use and ethics law. She has taught at the University of Virginia's Sorenson Institute for Political Leadership. During her time with the county, she has worked with elected officials and county staff members in dealing with unprecedented growth, including the establishment of the Rural Crescent, which is designated for low-density development.

Connaughton said supervisors were "dumbfounded" when she announced her plans to resign during a private discussion of her job performance. He said that there were no issues of contention and that everyone agreed she had done an excellent job. Connaughton said the timing might be due to the fact that Pandak's review had been pushed back several weeks because of other legal business, and that it was the last meeting before the board takes its August recess.

"It was another exceptional year for her and her office," said Connaughton, who is also an attorney. "She is at the top of her game. She's not just simply well known in the community, but one of the leading public attorneys and an expert in land use and ethics.

"I wouldn't be surprised if she continues to work -- at her leisure and schedule," he said. "We will really miss her. She's done an exceptional job for the county.''