Ms Linda Tripp, whose taped conversations with Ms Monica Lewinsky eventually led to the impeachment of President Bill Clinton, was indicted yesterday on two counts of violating Maryland state wiretap laws.
One count accused Ms Tripp of illegally taping telephone conversations with Ms Lewinsky without the former White House intern's permission and the other dealt with Ms Tripp's disclosure of those conversations to Newsweek magazine.
Ms Tripp and her attorneys are expected to challenge the indictments since she was granted immunity from prosecution by independent counsel Mr Kenneth Starr in his investigation of Mr Clinton's affair with Ms Lewinsky.
"Immunity will be a problem, but we will face it in the future," said Mr Stephen Montanarelli, the Democratic Maryland state prosecutor who led the grand jury investigation. Mr Montanarelli said he expected to "win because of the evidence we have".
Critics of the investigation have claimed that Ms Tripp is being prosecuted under laws rarely used because she came forward with information about Mr Clinton having an affair with Ms Lewinsky.
Howard County State's Attorney Marna McLendon, a Republican whose office had to approved continuing the prosecution, admitted prosecutions under the wiretap laws were "few and far between".
However, she said the grand jury made its decision to indict based on "evidence and the law".
Mr Stephen Kohn, one of Ms Tripp's lawyers, said the indictments would keep others from coming forward to expose wrong-doings by the powerful.
"Any such indictment will have a chilling effect on witnesses who have the courage to document and report the official misconduct," he said.