A Christian couple accused of blasphemy were beaten to death by a mob of 1,500 and their bodies thrown in a furnace this month in the latest in a spate of lynchings in conservative Pakistan.
A day later, a policeman hacked a man who had been accused of blasphemy to death with an axe while he was in custody.
Pakistan's tough blasphemy laws can include the death penalty, but critics say they are often used to settle personal disputes.
Such incidents have been met with general condemnation in the past, but little action has been taken against either the perpetrators or instigators -- a factor, say activists, driving a rise in such crimes.
But for lawyer Asma Jahangir, recently given France's highest civilian award and Sweden's alternative to the Nobel prize for her decades of rights work, the response to the Christian couple's killing offers hope for change.
"There is a positive development, that religious scholars and parties including Jamat-e-Islami went there and came forward against the incident, which is a good omen," she told AFP at her offices in the eastern city of Lahore.
Pakistan's religious right has for decades used supposed threats to Islam to stoke up support in a country where 97 per cent of the population are Muslims.
But Jahangir said the mounting number of gruesome vigilante cases was now forcing even those who had traditionally been the law's most vocal supporters to pause.
The All Pakistan Ulema Council, a leading clerical body, has chastised the government for failing to act and pledged that in the case of the Christian couple, justice for the victims must be served.
The former UN special rapporteur on religion has braved death threats, beatings and prison time to win landmark human rights cases and stand up to dictatorship.