Gunmen have killed Pakistan's lead prosecutor investigating the assassination of former prime minister Benazir Bhutto as he was driving to court, throwing a case that also involves the country's former ruler Pervez Musharraf into disarray.
In the southern city of Karachi, gunmen on motorcycles killed an anti-Taliban election candidate and his son, and a political activist in two other attacks.
The government prosecutor who was gunned down, Chaudhry Zulfikar Ali, was at the helm of a number of controversial cases, including the 2007 Bhutto assassination in which Mr Musharraf is accused of involvement. He was also prosecuting militants linked to the 2008 terror attack in the Indian city of Mumbai.
Mr Ali was on his way to a court in Rawalpindi, next to Islamabad, when gunmen fired at him, hitting him in the head, shoulder and chest, and then fled in a taxi and on a motorcycle. The prosecutor was shot at least 13 times and his car was pockmarked with bullets and the windshield shattered.
He then lost control of his car, which hit a woman passer-by and killed her, said police. Mr Ali's guard returned fire and is believed to have wounded at least one of the attackers. The guard also was injured. Police have launched a search for the gunmen.
Bhutto's husband, President Asif Ali Zardari, strongly condemned the prosecutor's murder and called for a thorough investigation. A motive for the killing was unclear.
Government prosecutors have accused Mr Musharraf of being involved in the Bhutto assassination and not providing enough security to Pakistan's first female prime minister. Mr Musharraf, who was in power when Bhutto was killed, has denied 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 Mr Musharraf returned in March after four years in exile.
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 later banned Mr Musharraf from running for public office for the rest of his life. He 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.