Islamabad, Pakistan (CNN) -- Gunmen in Pakistan killed a leading prosecutor working on high-profile terrorism cases and an anti-Taliban politician and his son, the latest violence ahead of next week's national elections.
Chaudhry Zulfiqar Ali was heading to a court in Rawalpindi, where he was trying a case stemming from the death of former Prime Minister Benazir Bhutto, who was assassinated while she was campaigning for her party.
Ali's attackers opened fire on his car as it passed through an Islamabad neighborhood, police said.
He was rushed to a hospital but died before arrival, said hospital spokesman Dr. Wasim Khawaja.
The ambush also wounded his bodyguard, whom authorities assigned to protect him after he received threats from the Pakistani Taliban, according to police spokesman Javed Hussain.
The unidentified gunmen fled and are still at large, police officials said.
In Karachi, gunmen on a motorbike shot and killed Sadiq Zaman Khattak and his 4-year-old son when they were leaving a mosque, said Zahid Khan of Awami National Party, an anti-Taliban liberal party.
Khattak, representing the Awami National Party, had been a candidate for a seat in the National Assembly. No one claimed responsibility for the attack, and Khan blamed the "interim government" and election officials.
The Taliban have threatened the Awami National Party and another liberal party, the Muttahida Quami Movement. The group has claimed responsibility for some deadly attacks against those party members.
In a statement, Pakistani President Asif Ali Zardari strongly condemned the attack on Ali and called for an investigation to "expose the real culprits involved in the murder."
Bhutto had returned from a self-imposed, eight-year exile to campaign for the Pakistan People's Party in the country's general elections in 2007. She escaped one attempt on her life but was killed on December 27, 2007, by a 15-year-old suicide bomber while campaigning in Rawalpindi, the seat of Pakistan's military.
Bhutto twice was prime minister and was the country's first woman to hold the office.
Ali had linked the assassin's alleged facilitators, whom he was prosecuting, to the Pakistani Taliban, an allegation the court has yet to confirm.
The Pakistani Taliban, who are closely linked with their namesake in Afghanistan and with al Qaeda, operate in the ungoverned area that sits on the border of Pakistan and Afghanistan.
Police officials have also been arrested in the investigation, which has lasted nearly six years.
Ali was also involved in the case of the terror attacks that struck Mumbai, India, in November 2008.
Ten heavily armed men, some from Pakistan, attacked landmarks there, including high-end hotels, the historic Victoria Terminus train station and the Jewish cultural center Chabad House.
They killed more than 160 people in three days.
Musharraf's party calls for election boycott
The All Pakistan Muslim League -- the party of former President Pervez Musharraf -- is calling for a boycott of the country's May 11 parliamentary elections, the league said Friday.
The party's Central Executive Committee unanimously determined that Musharraf is being "victimized." And that's a "clear indication that the upcoming elections in Pakistan will not be free and fair," Musharraf spokesman Raza Bokhari said.
The league said that "the stage is being set to enable pro-Taliban politicians in stealing the elections" and "urged the people of Pakistan, especially the Youth of Pakistan, to see through this farce, stand up to Save Pakistan and join the APML in this boycott."
Musharraf resigned as president of Pakistan in 2008 after nine years in power and went into exile the following year, living in London and Dubai. He came back to Pakistan recently under heavy security but intending to return to political life.
However, he has faced stiff barriers.
After his return, Musharraf was placed under house arrest by an anti-terrorism court over allegations he illegally ordered the detention of judges in 2007. He denies the charges against him.
The ex-military strongman still has to face two other cases dating from his time in power.
The first relates to claims he did not do enough to protect Bhutto's life weeks before an election in which she hoped to return to office.
Musharraf is also accused of ordering his troops to kill Nawab Akbar Bugti, a popular tribal leader, in the volatile province of Balochistan, in 2006.
Just recently, the high court in Peshawar banned Musharraf from politics for life, a move he can appeal.
CNN's Saima Mohsin contributed to this report.