Dr Harry Hagopian was speaking after Turkey's President said if the country's parliament wants to reintroduce capital punishment, he will approve it.
The statement follows a failed coup attempt on Friday.
Turkish authorities have dismissed nearly 9,000 police officers, public officials and others, while detaining thousands more alleged to have been involved in the attempted coup.
Turkey's President Recep Tayyip Erdogan addresses his supporters gathered in front of his residence in Istanbul.
Dr Harry Hagopian, a international lawyer and church consultant, told Premier's News Hour taking human life will not solve problems.
He said: "We do not agreed that it is possible to kill or take any human life, no matter not egregious the crime. There are ways in law of punishing people, making sure they stay in jail or that they face retribution."
He went on: "It doesn't mean we have to act as judge and jury and decide on killing a lot of those people, whose involvement from afar or from near in this coup might well be proven in the weeks ahead."
He said Turkey only abolished the death penalty 12 years ago.
"If it is pushed through parliament, there is a possibility it might be adopted, and then the president would sign the bill," he said.
"But I would be very sad if that were to happen because that would be a huge step backwards."
Turkish president Recep Tayyip Erdogan has refused to rule out bringing back the death penalty, telling broadcaster CNN: "There is a clear crime of treason."
He added that it would be up to parliament to make the decision.
Prime minister Binali Yildirim (pictured) said 232 people - including 208 government supporters he called "martyrs", as well as 24 coup plotters - died in the unrest.
The atmosphere following the coup attempt has seen tensions between Turkey and the West rise.
US and European officials are urging restraint, while Ankara insists Washington should extradite an exile accused of orchestrating the plot.
Reacting to the large number of arrests in the military and the judiciary, as well as Mr Erdogan's suggestion that Turkey could bring back the death penalty, western officials are urging Turkey to maintain the rule of law.
Meanwhile, Foreign Office officials have received no reports of British casualties during the attempted coup in Turkey, the Government has said.
Listen to Premier's Antony Bushfield speak to Dr Harry Hagopian here:
