The three men were found guilty of inciting attacks against Muslims in 2000. The BBC reports that there has been sporadic violence on the island since the executions.
Rev. Irianto Kongkoli was shot in the head while shopping for construction materials in Palu, the capital of Central Sulawesi province.
According to a Reuters report, the cleric had finished bargaining for some tiles when someone called him back into the store. When he entered, two shots were fired at the back of his head.
Central Sulawesi governor Bandjela Paliudju told reporters he believes the killing may have been linked to last month's executions. Kongkoli was known to be outspoken and to have led Christian protests against the executions.
A police investigation is underway.
.- A Protestant minister was shot dead on Indonesia's Sulawesi Island, where tension between Christians and Muslims have been mounting since the execution of three Catholic men, whom supporters say were innocent.