The bomb attack at the electoral office in April killed at least 13 people.
A series of bomb blasts and other attacks occurred in the run-up to and after Nigeria’s parliamentary, presidential and state elections in April.
Much of the violence has been claimed by an Islamist sect known as Boko Haram, which has mainly operated in the northeastern region of the country and has previously targeted churches in a nation roughly divided in half between Christians and Muslims.
Attacks have intensified in recent weeks and other parts of the country also have been targeted.
From wire dispatches and staff reports