The attackers set the Divisional Police Headquarters, located in Ehime Mbano local government area of the state, on fire on Tuesday, April 6, 2021.
They also freed suspects who were detained at the facility, according to media reports yet to be confirmed by officials.
A police constable sustained a minor gunshot wound during the previous attack on the headquarters in Owerri on Monday, April 5.
The attackers set dozens of cars on fire and also freed 1,844 inmates at the Owerri Custodial Centre.
President Muhammadu Buhari described the twin attack as an act of terrorism and directed security and intelligence agencies to fully mobilise and ‘go after the terrorists’.
The Nigeria Police Force has blamed the separatist group Indigenous People of Biafra (IPOB) for the attacks.
The group was designated a terrorist organisation by the government in 2017 after its members were involved in tense standoffs with Army troops.
The group’s Eastern Security Network (ESN) has been the alleged perpetrator of a string of attacks on security forces that have left dozens of officers dead in the southeast region over the past few weeks.
IPOB spokesperson, Emma Powerful, has strongly distanced the group from the attack.
He said IPOB was formed on the principle of peace and would not compromise its principles.