The main suspect in a Christmas Day bomb attack on a church just outside Nigeria's capital escaped within 24 hours of his arrest and the police commissioner in charge has been suspended, police said on Wednesday.
Islamist sect Boko Haram claimed responsibility for the bombing of St. Theresa Catholic Church in Madalla, on the outskirts of Abuja, that killed 37 people and wounded 57.
Police arrested Kabiru Sokoto on Tuesday and while they were taking him from police headquarters to his house in Abaji, just outside Abuja, to conduct a search there, their vehicle came under fire.
"In the course of undertaking this important procedure, the Policemen on escorts with the suspect were attacked by the suspected sect gang members and in the process the suspect freed," police spokesman Olusola Amore said in a statement.
"The Police view this development as a serious negligence on the part of the Commissioner of Police and have since been queried and suspended him from duty," he said.
Last year was the second in a row that Boko Haram has attacked churches at Christmas. Its strikes are becoming deadlier and more sophisticated, and have raised fears that the militants are trying to ignite sectarian strife between Nigeria's largely Muslim north and Christian south.
Boko Haram, meaning "Western education is sinful" in Hausa, has also been blamed for a campaign of shootings and bombings against security forces and authorities in the north.
Attacks in and around the capital - including one on the UN headquarters in August that killed at least 24 people - suggest the group is trying to raise its profile and radiate out from its heartland in the northeast.