The Department of State Services, DSS, and the National Intelligence Agency, NIA, are reportedly probing how Natasha Akpoti-Uduaghan, the senator representing Kogi Central, attended the Inter-Parliamentary Union, IPU, meeting in New York without official nomination.
Reports say the probe is seeking to uncover how she secured accreditation, who facilitated her trip, and whether her participation was orchestrated to embarrass the Nigerian government.
The IPU, a global organisation of national parliaments, requires member countries to nominate delegates before meetings.
Akpoti-Uduaghan was said to have attended the IPU meeting, despite not being authorised.
The joint investigation by the DSS and NIA, it was learned, was triggered by complaints from the Senate.