A police source said the deceased visited his girlfriend identified only as Bridget at about 10:00a.m. and was preparing to leave after they made love.
The woman, who reported the matter at the police station, said she was in the bathroom when her lover slumped and died.
The Gwarinpa Divisional Police Officer, CSP Nuruddeen Sabo, said the woman was in custody and the body has been taken to Asokoro District Hospital for autopsy.
Investigation is ongoing, he added.