The proscription of the Indigenous People of Biafra (IPOB) by the Federal High Court on 20 September 2017 — following Operation Python Dance II — and the extradition and rendition of Nnamdi Kanu from Kenya on 19 June 2021 produced the institutional vacuum into which the 'Unknown Gunmen' phenomenon expanded. The Eastern Security Network (ESN), created by Kanu in December 2020 as the armed wing of IPOB to protect Eastern villages against Fulani-identified attacks, formally disowned the campaign of attacks on Nigerian state institutions; in practice ESN cells and other armed groups operated under the same 'Unknown Gunmen' nomenclature.
From early 2021 attacks on police stations, INEC offices, military checkpoints, prisons (notably the Imo Correctional Centre attack of 5 April 2021, 1,844 inmates released) and the residences of Igbo politicians who criticised IPOB became continuous across Abia, Anambra, Ebonyi, Enugu and Imo. The Monday 'sit-at-home' order issued by Kanu's deputy Simon Ekpa from Finland — enforced by armed groups attacking traders who opened shops — paralysed the South-East economy: Chamber of Commerce estimates put cumulative losses to the regional economy at ₦7.6 trillion between 2021 and 2024.
Federal response — Operation UDOKA (2021) and Operation Restore Peace (2022) — produced mass arrests and disputed-circumstance deaths (Auwal Aliyu, Ozoemena Cyriacus, multiple cases documented by Amnesty International) but no political settlement. Kanu remains in Department of State Services custody at Asokoro, Abuja, with his trial perpetually adjourned; the Court of Appeal's order for his release of 13 October 2022 was effectively nullified by the Supreme Court restoration of the charges in December 2023.
Cumulative dead 2021–2025: at least 1,000 (security personnel, suspected gunmen, civilians caught in crossfire). The exact pattern — federal proscription of the political vehicle producing an unaccountable armed successor — is the pattern of the Boko Haram emergence after the killing of Mohammed Yusuf and of the MEND emergence after the arrest of Dokubo-Asari. The state-violence remedy to a political problem keeps reproducing the political problem.