Charles Antwi had confessed to a circuit court earlier that he had wanted to overthrow President Mahama but pleaded not guilty.
The circuit court, presided by Justice Francis Obiri, changed his plea and convicted him.
Charles had gone to the Ringway Gospel Centre branch of the Assemblies of God church where the president and his family fellowship to assassinate him.
The president and his family were not in church that day.
Security personnel arrested Charles Antwi and within 48 hours he was handed a 10 year jail term for the illegal possession of a firearm.
But this was condemned by many who thought the trial was unusually swift.
Mother of Charles said the sentence was inappropriate because her son had a mental problem.
Constitutional expert, Professor Stephen Kwaku Asare described the ruling as “despicable” and “unheard of.”
A legal practitioner, Mathias Yakah also questioned the ruling saying “it is totally wrong in law to sentence someone who has pleaded not guilty…he must be made to go through full trial…,”
Another lawyer, Yaw Oppong, described the ruling as severe adding that it was a “travesty of justice”.
A human rights lawyer, Francis Sosu, said the verdict was a complete “miscarriage of justice” and a “violation of the Mental Health Act.”
He went to the high court with a writ for an order of certiorari to reverse the sentence.
Last week the Attorney-General also filed a motion at the Accra High Court seeking to quash the 10-year jail sentence.
According to the A-G, the sentence was wrongful.
It, however, opposed the case brought by Francis Sosu, preferring instead, to appeal the verdict because in its opinion, the conviction was proper, it was only the sentence that was wrongful.
Principal State Attorney, Evelyn Keelson, argued the remedy could not be obtained through a writ of certiorari.
What ought to happen and which the A-G’s department was seeking in court was an appeal against the sentence.
Anything short of that, the state attorneys argued, could lead to a situation where officials of the Bureau of National Investigations would pick the convict up if the High Court overturns the decision.
Francis Sosu vehemently disagreed, Joy News’ Latif Iddrisu reported.
He argued the circuit court’s decision was such a perversion it could not be allowed to stand in any form.
Having listened to both sides, the court set October 31, to give its ruling on the matter.