The primary statutory authority for this sentence is Section 260 of the Kebbi State Penal Code Law, 2021, which criminalizes "unnatural offences." While the exact wording of Kebbi State's provision isn't publicly available in full, similar provisions in northern Nigerian penal codes typically define "unnatural offences" as carnal intercourse against the order of nature, which judicial interpretation has extended to include same-sex sexual acts and anal intercourse.
Life Imprisonment for Child Sexual Assault: Legal Basis and Constitutional Considerations by Lawson Akhigbe
Centre for Nigeria Progress 