Otu said the convicts were young men who ordinarily should be going about their legitimate businesses to make it in life.
Justice Sunday Otu, who handed down the sentence upon conviction in Lokoja on Friday, said the prosecution had proved its case beyond reasonable doubt by cogent, credible, compelling and positive evidence.
Otu said the convicts were young men who ordinarily should be going about their legitimate businesses to make it in life but decided to go against the law to acquire wealth through criminal means.
He said that the court in reaching its decision saw the need to send a very strong warning to the society and at the same time considered their age.
The judge, also, sentenced them to eight years for criminal conspiracy under section 97(1); another eight years for armed robbery under section 298(2) of the Penal Code.
Otu also sentenced the convicts to seven years for illegal possession of firearms under Section 3 of the Robbery and Firearms (Special Provisions) Act CAP R11 LFN 2004.
He said that the sentences would run concurrently taking cognizance of the period they had spent in detention awaiting trial.
The prosecuting counsel, Mohammed Abaji, said the convicts with others now at large, on April 25, 2015 attacked and robbed an SSS officer, Salihu Zuberu, on duty at Save House, GRA, Lokoja.
Abaji said the convicts who robbed Zuberu at gun point, carted away his Nokia 607 I-phone, a tecno, a HP Laptop, mini-Uzi machine gun and N27,000 cash.
He said the report by the security officer led to the investigation of the matter resulting in the recovery of the mini-uzi machine gun and some of the looted items.
The convicts had raised alibis saying that they were not at the scene of the alleged robbery but other victims who they had earlier robbed came to testify against them.
The News Agency of Nigeria (NAN) reports that the prosecution raised three fundamental questions for determination by the court which were determined in its favour.