Sajith Premadasa, ruling party presidential candidate promised to flip the pardon once in power.
More than 250 Sri Lankan convicts aged over 65 have been given amnesty just days after the president sparked outrage by pardoning the well-connected killer of a Swedish teen, officials said Thursday.
Jude Jayamaha, the scion of a wealthy Sri Lankan family and convicted in 2005 of murdering Yvonne Jonsson, walked free from death row on Saturday after Maithripala Sirisena's pardon.
His release prompted outrage from the victim's family, rights groups, and people on social media- and also initiated a mini-rebellion from inmates at the country's main high-security prison, who demanded similar treatment.
In an apparent bid to calm the situation, Sirisena- due to step down after elections on Saturday- issued a pardon for some 267 prisoners aged over 65.
"We have now got orders from the president and the prisoners will walk free today and tomorrow," a justice ministry official told AFP.
Officials said all those granted pardons were serving time for offences other than rape or murder.
Jayamaha was initially sentenced to 12 years in jail for the brutal murder of Jonsson, who was 19. His trial heard her skull had been fractured into 64 pieces.
An appeal court upgraded the sentence to the death penalty, a decision reaffirmed by the Supreme Court in 2014.
Ruling party presidential candidate Sajith Premadasa said earlier this week he would consider every legal option to overturn the pardon if elected.
There are around 375 people on death row in Sri Lanka, but the country has had a moratorium on executions since 1976.
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