The Department of State Services on Wednesday presented fresh testimony before the Federal High Court in Abuja, alleging that Tukur Mamu, the self-acclaimed negotiator in the 2022 Abuja–Kaduna train attack, funded a sudden luxurious lifestyle with proceeds he allegedly received during ransom negotiations.

Testifying behind a protective screen, the sixth prosecution witness said Mamu began living “far above his means” after inserting himself into discussions between families of abducted passengers and the terrorist group responsible for the attack.

Led in evidence by DSS counsel David Kaswe, the witness told the court that during the negotiations, Mamu’s lifestyle “changed dramatically.” Under cross-examination, he claimed the defendant sponsored a foreign trip to Egypt for himself and four family members—who were with him at the time of his arrest—and purchased two cars within the same period.

When questioned further, the witness admitted he had never met Mamu before the incident and could not confirm the defendant’s net worth prior to the attack. The defence, led by Senior Advocate of Nigeria Johnson Usman, argued that Mamu already owned vehicles—including a Toyota Venza and Mercedes Benz E350—and had travelled abroad multiple times with family members long before the 2022 attack.

Mamu, currently being tried for alleged terrorism financing, was arrested by Egyptian authorities on September 7, 2022, before being repatriated to Nigeria. Prosecutors allege he positioned himself as an intermediary in the train attack negotiations solely for personal gain, claiming he collected ransom funds and acted outside any government mandate.

In earlier proceedings, the witness said Mamu was offered ₦50 million by the leader of the terrorist group as a personal reward. The court was played an audio clip allegedly featuring the voice of “Shugaba,” the group’s leader, instructing Mamu to “take ₦50 million” for himself from the ransom he was helping to deliver.

According to the DSS, investigators extracted audio evidence from Mamu’s Samsung tablet and two phones seized after his arrest. The witness said the devices contained conversations between Mamu and various members of the terrorist group.

Continuing his testimony, PW-6 told the court that Mamu operated independently and was never authorised by the Federal Government or the Chief of Defence Staff Committee—which was officially tasked with negotiating the release of passengers. He alleged that Mamu encouraged terrorists to discuss ransom demands directly with victims, confirmed payments on their behalf, handled cash transactions, and even advised the group on building a website.

He also testified that a large undisclosed sum recovered from Mamu’s Kaduna residence exceeded permissible legal limits, reinforcing concerns about his sudden wealth.

Reading from his investigative report, the witness stated:
“Mamu was not mandated by the government to negotiate with terrorists. He acted for his benefit, collected ransom on their behalf, confirmed amounts, facilitated delivery, possessed an illegal firearm, and provided technical information to the terrorists. His lifestyle changed significantly during the negotiations.”

However, the defence challenged the credibility of the investigation, questioning whether the DSS verified Mamu’s travel history despite having operatives at all Nigerian airports. The witness admitted he did not examine the defendant’s passport, insisting it was unnecessary because he relied on a preliminary report.

The defence also argued that victims were the ones who introduced names of potential negotiators to the terrorists, and that Mamu only stepped in after the release of a single hostage.

Justice Mohammed Garba Umar adjourned proceedings to January 29, 2026, for the continuation of cross-examination.