Gunmen have killed Pakistan's lead prosecutor investigating the assassination of former prime minister Benazir Bhutto, throwing the case that also involves former ruler Pervez Musharraf into disarray.
Chaudhry Zulfikar was at the helm of a number of controversial cases, including the 2007 Bhutto assassination in which Musharraf is accused of involvement.
He was also prosecuting militants linked to the 2008 terror attack in the Indian city of Mumbai.
Mr Zulfikar was driving to a court in the capital Islamabad when gunmen fired at him from a taxi, hitting him in the head, shoulder and chest, said a police spokesman.
He then lost control of his car, which hit a woman passer-by and killed her, said another police source.
Mr Zulfikar's guard, Farman Ali, returned fire and is believed to have wounded at least one of the attackers, but was also injured in the attack.
The attackers fled after killing Mr Zulfikar, police said, and a massive search has been launched to find them.
The motive for the killing is not yet clear, but his involvement in the two particularly high-profile cases is likely to be scrutinised closely.
Government prosecutors have accused Musharraf of being involved in Ms Bhutto's assassination and not providing enough security to Pakistan's first female prime minister.
Musharraf, who was in power when Ms Bhutto was killed, denies the allegations. At the time of the attack, he blamed the assassination on the Pakistani Taliban.
The Bhutto case has lingered for years in the Pakistani court system. A number of alleged assailants are on trial but no one has been convicted. The case burst into the headlines when Musharraf returned in March after four years in exile.
Mr Zulfikar was also the government's lead prosecutor in a case related to the 2008 terrorist attack on Mumbai that killed 166 people. The attack was blamed on the Pakistan-based militant group Lashkar-e-Taiba.
Pakistan has put seven men on trial on charges they assisted in the Mumbai siege, but the trial has made little progress.
India has criticised Pakistan for not doing more to crack down on the militants blamed for the attack. Hafiz Saeed, the head of a group believed to be a front for Lashkar-e-Taiba, remains free, and many believe he enjoys the protection of the government.
Lashkar-e-Taiba was founded years ago with the help of Pakistani intelligence to put pressure on India over the disputed territory of Kashmir.
Musharraf returned to Pakistan to make a political comeback despite Taliban death threats and a raft of legal cases against him, but his fortunes have gone from bad to worse since he arrived.
Judges barred him from running in the May 11 parliamentary election not long after he arrived because of his actions while in power. A court in the north-western city of Peshawar went further this week and banned Musharraf from running for public office for the rest of his life - a ruling the former military strongman plans to appeal against.
Musharraf is under house arrest on the outskirts of Islamabad in connection with several cases against him, including the Bhutto case. He also faces allegations of treason before the Supreme Court.
Mr Zulfikar was heading to a hearing related to Musharraf and the Bhutto case at a court in Rawalpindi, near Islamabad, when he was killed, said police.
Musharraf seized power in a military coup in 1999 when he was serving as army chief and ruled for nearly a decade until he was forced to step down in 2008 because of growing discontent with his rule.
Though Pakistan has experienced repeated violence, it is rare for such an attack to happen in the capital, which is home to high-ranking government and military officials, diplomats and international aid workers.
President Asif Ali Zardari strongly condemned the prosecutor's killing and called for a thorough investigation.