U.S. jurors in Washington have begun a second day of deliberations Thursday in the case of a former White House aide accused of lying about his role in the disclosure of a CIA agent's identity.

The jury of eight women and four men heard closing arguments in the case on Tuesday.

Prosecutors said witnesses have proven that Lewis "Scooter" Libby deliberately and repeatedly lied about how he found out that Valerie Plame was a CIA agent in an attempt to protect himself and to protect his boss, Vice President Dick Cheney.

Several journalists have testified they learned of Plame from Libby.

Plame is married to former diplomat Joseph Wilson, who openly criticized the Bush administration about its reasons for launching the 2003 invasion of Iraq.

Libby has been charged with perjury and obstruction of justice. He faces a maximum of 30 years in prison if found guilty.

Prosecutors say Libby leaked the information as part of a White House effort to discredit Wilson. Chief Prosecutor Patrick Fitzgerald said the disclosure of Plame's identity "cast a cloud" over the White House and over Cheney in particular.

The defense argued that Libby had a lapse of memory.

Some information for this report was provided by AP.