Mr Iheka, a lawyer, made the announcement on Tuesday during an interactive session with journalists in Owerri.
He said that Mr Chigbu was murdered in a “extrajudicial” manner by the Nigerian Army.
He challenged army officials to find and prosecute the team of soldiers who committed the act in order to prevent a similar incident in the future.
The deceased, who was from Umuocham in Imo’s Ngor-Okpala Local Government Area, was killed on April 30 in Owerri’s Akwa-Akuma.
Mr Chigbu’s death, which left behind a pregnant wife and two underage children, was characterised as unfortunate by the activist.
“According to the soldiers, he disobeyed traffic laws and fired from the back of his car. However, there was a bloodstain on the leather seat of his new Toyota Camry, despite the fact that no bullet had entered the backseat.
“It is not written into the country’s Constitution that security personnel can fire at or even kill traffic law violators.
“As a result, I strongly condemn this extrajudicial, ludicrous, insensible, and inhuman act. I understand that our security personnel are there to protect us, but this must be done legally so that the purpose of their operations is not defeated,” Mr Iheka explained.
Meanwhile, Lt. Babatunde Zubairu, spokesman for the Nigerian Army’s 34 Artillery Brigade at Obinze, near Owerri, confirmed the incident.
Mr Zubairu said, “It happened, and I have spoken about it numerous times.”
“A petition has been written by the deceased’s family members and copied to the 34 Artillery Brigade, Obinze, and the Army Headquarters.”
He encouraged reporters to be impartial in their coverage of the incident.