After 85 days in jail for refusing to name her source, New York Timesreporter Judith Miller broke her silence and appeared before a grand jury investigating whether anyone in the Bush administration illegally leaked a CIA operative's identity.
Ms Miller, who was freed on Thursday, testified about her conversations with a top aide to Vice President Dick Cheney, lawyers said. She said she agreed to testify about the conversations after receiving what she called a "personal, voluntary" waiver of confidentiality from her source.
Ms Miller did not identify that source by name, but lawyers involved in the case said it was Mr Cheney's chief of staff, Lewis Libby. Ms Miller said the source had conveyed an explicit waiver in the form of a letter and a phone call to her in jail.
After obtaining her waiver, Ms Miller said her lawyers secured an agreement with Patrick Fitzgerald to narrow the scope of her testimony to her conversations with that single source.
Lawyers close to the case said Ms Miller's testimony appeared to clear the way for prosecutor Patrick Fitzgerald to wrap up his two-year-old inquiry into who leaked CIA operative Valerie Plame's identity and whether anyone broke the law in doing so.
Ms Plame's diplomat husband, Joseph Wilson, said the administration had leaked her name, damaging her ability to work undercover, to get back at him for criticizing President George W Bush's Iraq policy.
The lawyers said Mr Fitzgerald could now move quickly to bring indictments in the case, or he could conclude that no crime was committed and end his investigation and possibly issue a report on his findings.
Mr Fitzgerald had indicated he could wrap up his investigation once he obtained Ms Miller's testimony.