Salman Taseer, Governor of Punjab, was showered with bullets by his own bodyguard Mumtaz Qadri.
Over 100 clerics were arrested in Punjab province on Wednesday for attempting to hold a rally in Lahore to "celebrate" the sixth anniversary of the assassination of the then Punjab Governor Salmaan Taseer.
Mr Taseer, Governor of Punjab and an outspoken advocate for reform of the blasphemy laws, was showered with bullets by his own bodyguard Mumtaz Qadri.
Demonstrators belonging to the various Sunni groups planned the rally.
The clerics were given a go-ahead to hold a rally on Mall Road but not in Gulberg in Lahore. Heavy police contingents were deployed at Kalma Chowk and roads blocked with containers. The Metro Bus Service was suspended after a few clerics and their followers entered its track.
Mr Taseer, who had angered religious zealots with his statements against the country's controversial blasphemy laws, was killed in Islamabad's Kohsar Market on January 4, 2011. His assailant, Mumtaz Qadri, who later admitted the killing, was subsequently executed in Rawalpindi's Adiala Jail in 2016.
Nearly a year after the hanging of Mr Qadri, a shrine was being built in his memory in Bhara Kahu, not far from the capital where Mr Taseer was gunned down.
A month after Mr Taseer's killer was executed, a mob of pro-Qadri protesters converged on the capital and besieged Islamabad's Red Zone for nearly a week.