Pakistan's top judge, Chief Justice Iftikhar Chaudhry, has been suspended by President Pervez Musharraf for "misuse of authority".
Mr Chaudhry led the way in investigating alleged political disappearances
The president has asked the Supreme Judicial Council, which oversees the judiciary, to investigate the charges.
As the main judge in the Supreme Court, Mr Chaudhry had a reputation for taking a firm line against government misdemeanours and human rights abuses.
He has also faced criticisms over other aspects of his conduct.
The details of Mr Chaudhry's alleged offences are not yet clear.
Justice Javed Iqbal has been appointed as acting chief justice.
President Musharraf had received "numerous complaints and serious allegations for misconduct, misuse of authority and actions prejudicial to the dignity of office of the chief justice of Pakistan," the state-run Associated Press of Pakistan news agency reported.
Mr Chaudhry was summoned to explain himself to Gen Musharraf and Prime Minister Shaukat Aziz.
His case was then referred to the Supreme Judicial Council which will decide if Mr Chaudhry should be prosecuted.
The BBC's Syed Shoaib Hasan says that Mr Chaudhry was a highly controversial figure throughout his tenure.
He took up investigations into the highly sensitive issue of the disappearance of political activists allegedly detained illegally by the security forces.
Recently a number of private television stations carried reports about his son's appointment to a senior police post amid claims that he was not qualified for the position.
Last month a Supreme Court lawyer published an open letter to Mr Chaudhry criticising his behaviour towards Pakistan's bar association.