Najafi’s wife, Mitra Ostad, was murdered at her home in Tehran on Tuesday. Police found her body with several gunshots in her chest.
Najafi has reportedly gone to the Criminal Police headquarters in person and confessed to the murder.
Najafi had resigned from the post of Tehran’s mayor in April 2018, citing failing health for leaving the office.
A graduate of the Massachusetts Institute of Technology (MIT), 67-year-old Najafi was elected mayor of Tehran in August 2017.
Affiliated with the reformist political faction, he used to serve as the minister of education and the minister of culture in various administrations.
He also took the helm at Iran’s Cultural Heritage, Handicrafts and Tourism Organization (ICHTO) during President Hassan Rouhani’s first term, but resigned after six months.