A Department of State Services (DSS) investigator on Wednesday alleged that Tukur Mamu benefited from the ransom paid for victims of the 2022 Abuja-Kaduna train attack.

The operative made the claim while testifying as the sixth prosecution witness (PW-6) before Justice Mohammed Umar of the Federal High Court in Abuja, in Mamu’s ongoing terrorism trial.

Testifying behind a shield for security reasons, the witness told the court that DSS findings showed Mamu’s lifestyle changed during negotiations with the terrorists.

David Kaswe, DSS counsel led in evidence the PW-6 said the investigation revealed that Mamu encouraged ransom negotiations between the terrorists and victims’ families and handled ransom collection and confirmation.

According to the witness, Mamu collected money on behalf of the terrorists, facilitated its delivery, and possessed a firearm illegally.

He also said Mamu provided the terrorists with information on how to create a website and that cash recovered from him exceeded the limit permitted by law.

He added that Mamu did not share voice notes used in negotiations with the Chief of Defence Staff (CDS) Committee.

The investigator said Mamu had no authority to negotiate on behalf of the CDS Committee, which was mandated to handle the rescue process. Instead, he alleged, Mamu worked directly with the terrorists and benefited from the negotiations.

When asked about Mamu’s lifestyle change, the witness said Mamu was arrested with four family members whom he sponsored on a trip to Egypt.

He also said Mamu bought two cars during the negotiation period.

During cross-examination, Johnson Usman, SAN, Mamu’s counsel, questioned the thoroughness of the investigation.

The DSS witness admitted that although the agency has personnel at all Nigerian airports, he could not confirm whether Mamu and his family travelled to Egypt through Kano International Airport.

He also said he had never worked at an airport, had never travelled outside Nigeria, and did not check Mamu’s passport, despite it being in DSS custody.

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The witness also said he had not seen any formal DSS invitation to Mamu before or after the train attack, nor any document declaring him wanted.

He acknowledged that he did not know Mamu’s net worth, having never met him before the incident.

He maintained that the terrorists contacted several individuals suggested by the victims, but Mamu was the only person who agreed to take part in the negotiations.

He also said Mamu was not a member of the CDS Committee.

He confirmed that only one hostage was released before Mamu began engaging with the terrorists.

Justice Umar adjourned the case to January 29, 2026, for continuation of trial.