DSS spokesman, Peter Afunanya, confirmed the development in a statement on Wednesday.
Tukur Mamu was arrested in Cairo, the capital of Egypt while on his way to Saudi Arabia for lesser Hajj.
The DSS spokesman while confirming the development, said the negotiator was intercepted by Nigeria’s foreign partners on Tuesday.
“This is to confirm that Mamu, as a person of interest, was intercepted by Nigeria’s foreign partners at Cairo, Egypt on 6th September 2022 while on his way to Saudi Arabia,” the statement read.
“He has since been returned to the country, today, 7th September 2022, and taken into the Service’s custody.
“The act followed a request by Nigeria’s military, law enforcement, and intelligence community to their foreign partners to bring back Mamu to the country to answer critical questions on ongoing investigations relating to some security matters in parts of the country”.
Mamu had made headlines lately following his part in the release of the Kaduna train victims who were abducted on March 28.