Pakistan Tehreek-e-Insaf Sindh senior vice president, Zahra Shahid Hussain, was gunned down here on Saturday night, Geo News reported.
According to initial reports, unidentified gunmen shot her outside her residence in Defence Housing Authority (DHA) Phase IV here.
Earlier, the police had said that she was ambushed by two bikers who were lying in wait around the corner.
"The assailants opened fire on Zahra, 60, as soon as reached the gate of her residence. Apparently they were there to target her only", a police official told Geo News.
However, minutes later, SSP Nasir Aftab, claimed that according to what investigators had learned from Zahra's daughter and driver, the eyewitnesses, it was a street crime related murder.
"The PTI leader got killed resisting an armed roadside robbery", said SSP Aftab.
An eyewitness said that she had handed the attackers her belongings, but they shot her even then.
The shooters fled away with the booty leaving her seriously wounded.
Zahra was rushed to a hospital immediately, but succumbed to her injuries on the way, sources said.
According to sources in the private hospital, where she was pronounced dead, she was shot in the head twice, apparently from a point-blank range.
"One bullet, which entered her chin, went up through the head, and exited from the back of her head, became the cause of her death", sources said.
Her body was being shifted to Jinnah Post-graduate Medical Centre (JPMC) for medico-legal formalities.
PTI chief Imran Khan and spokesperson Shireen Mazari denounced the killing of their party leader and demanded justice without delay.
Imran Khan wrote on his Twitter account that he was shocked & deeply saddened by the brutal killing of Zara Shahid Hussain, who was like an elder sister to us. It was an act of targeted act, he added.
He held Altaf Hussain "directly responsible" for the murder, saying the MQM chief had openly threatened the PTI leaders and workers (over their staging sit-ins against vote rigging).
"The tragic incident is an act of blatant terrorism. The provincial government has completely failed in safeguarding the citizens", Mazari said.
Muttahida Qaumi Movement (MQM) chief Altaf Hussain has also condemned the killing. However.
According to PTI spokesman, Zahra Shahid Hussain was the founder member of Pakistan Tehreek-e-Insaf.