He added that denying the allegations is a lie.
DG Sowe recently testified before the commission and denied any knowledge of tortures at the NIA during his time as agent.
Cham, however, said Sowe was present when such maltreatment was inflicted on him during his detention at the NIA Headquarters in Banjul.
Narrating the event of his arrest, the witness explained that when he heard that there were drugs imported into the country by Bissau Guineans, he reported the matter to the drug squad for them to take action.
However, he said he was arrested and taken to NIA Headquarters in Banjul by Lamin Manneh and Dembo Mbaye for reporting the matter.
"I found Jim Drammeh, Ousman Sowe, Sukuta Jammeh, Alhagie Morr Jobe and others. In my presence, I heard some Bissau Guineans crying because they were beaten and cuffed their ankles and hands."
At the NIA, Cham stated that he was asked to undress which he did and was completely naked.
"They later asked me to go to the center where they were standing; and suddenly, they heard the screaming of a man called Ansumanna, who was crying because his private part was nearly cut off. They concentrated on that man and that was how I had the chance to dress up."
The witness continued that the Bissau Guineans were asked whether they knew or had seen him before, but they answered in the negative. He added that the NIA officers told him that the reason why he informed the drug squad about the drugs dealing was of his interest. He alleged he was locked in a cell with other five Bissau Guineans.
Cham further explained that he spent 28 days and was later accused of conspiracy to traffic in drugs. He narrated that they were taken to Banjul Magistrates’ Court where they were remanded.
He told the commission that the following day, they were taken to Brikama Magistrates’ Court but the case was later transferred to High Court where he was granted bail.
He said the court lasted almost two years before he was acquitted and discharged.
"This impacted my life a lot because I was very honoured in my community and in the end, only for them to hear that I was arrested for drugs dealing, it was shocking. My reputation as a leader in my community had been battered."